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Ask your Sponsoring Bonded Raytheon Tube Distributor about “Operator 25"' and the many other important advantages of being a Raytheon Bonded Electronic Technician.
RAYTHEON MaNuFACTURING COMPANY
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An Invitation...
To men who want to ‘go places” in TV SERVICING
Find out about this NEW, ALL-PRACTICE WAY
of becoming a Professional TV SERVICEMAN
If you have some Radio or Television experience, or if you know basic Radio- Television principles but lack experience— NRI’s new Professional Television Serv- icing course can train you to go places in TV servicing. This advertisement is your personal invitation to get a free copy of our booklet describing this training in detail,
Learn-by-Doing ‘‘All the Way’’
This is 100% learn-by-doing, practical training. We supply all components, all tubes, including a 17-inch picture tube, and comprehensive manuals covering a thor- ough program of practice. You learn how experts diagnose TV defects quickly. You see how various defects affect receiver per- formance—picture and sound; learn causes of defects, accurately, easily, and how to fix them. You do more than just build circuits. You get practice recognizing, isolating, and fixing innumerable troubles.
You get actual experience aligning TV receivers, diagnosing the causes of com- plaints from scope patterns, eliminating interference, using germanium crystals to rectify the TV picture signal, obtaining 4 2 ; pe ; x maximum brightness and definition by Train at home easily, quickly, for TV’s top servicing jobs. NRI’s
properly adjusting the ion trap and center- . os 2 6 ° . P ing magnets, etc. There isn’t room on this | Professional Television Servicing course includes a 17-inch picture
or even several pages of this magazine to the and all other tubes and components to build a complete TV
list all the servicing experience you get.
UHF & COLOR TV Making New Boom Receiver, Oscilloscope, Signal Generator, H.F. Probe. Complete Installing front-end channel selector strips training, including all equipment, available now for a low intro- in modern UHF-VHF Television receivers .
and learning UHF servicing problems and ductory price—under $200 on easy ferms.
their solution is part of the practice you get. To cash in on the coming color TV boom you’ll need the kind of foundation in knowl- edge and experience this training gives.
Get Details of New Course Free
Once again—if you want to go places in TV servicing, we invite you to find out what you get, what you practice, what you learn from NRI’s new course in Professional Television Servicing. See pictures of equip- ment supplied, read what you practice, Judge for yourself whether this training will further your ambition to reach the top in TV servicing. We believe it will. We believe many of tomorrow’s top TV serv- icemen will be graduates of this training. Mailing the coupon involves no obligation, RADIO & TELEVISION NEWS is published monthly by Zif-Davis Publishing Company, William B. Ziff, Chairman of the Board (1946-1953), at 64 E. Lake St., Chicago 1, Tl Entered as second-class matter July 21, 8, at the Post Office, Chicago, Ill., under the act of March 3, 1879. Authorized by Post Office Depart
. 1948, t 3 ai ment, Ottawa, Canada, as second-class matter. SUGSSCRIPTION RATES: Radio & Television News—one year U. S. and possessions, and Canada $4.00; Pan-American Union countries $4.50; all other foreign countries $5.00.
4 |
National Radio Institute, Dept. 7 AET 16th and U Sts., N.W., Washington 9, D.C,
Please send my FREE copy of “How to Reach the Top in TV Servicing.” I understand no salesman will call.
Name.......
Address See Es i
January, 1957
COVER PHOTO: The Remington Rand “Univac”, installed in the accounting offices of Consolidated Edison in New York, the of cus tomers’ ‘bills and saves untold hours of operations.
(Ektachrome by Seymour Zweibel, Gotham Film Productions, Inc.)
RADIO. |
TELEVISION
NEWS
Reg. U. S. Pat. Off. Radio News Trademark pat a U. S. Pat. Office e Television News Trademark Reg. U. S. Pat, Office.
First in radio -
Glitelan - aadie - olddhiidcs
Average Net Paid Circuluation 258,790
CONTENTS JANUARY, 1957
EDITORIAL—-INDUSTRY NEWS For the Record Spot Radio News New TV Grants Since Freeze Lift Behind the Giant Brains (Part 1) The “Univac”—An Electronic Brain for Industry Low Plate-Potential Tubes
What’s Ahead for the TV Industry Transistor Life Tests
FIDELITY AND AUDIO Power Requirements for Hi-Fi David Hafler Electronic System for 2-Way Speaker Operation Robert G. Vaughn Buying a Tone Arm N. H. Crowhurst A New Master-Control Preamp Realistic High Fidelity—The Power That Drives the Speaker
H. A. Hartley
Bert Whyte
SERVICING
Television-Radio From Sun to Sound Perry Sheneman Sylvania’s New Color TV Line Walter H. Buchsbaum Distributors and Service Technicians Join Hands William Leonard Design Features of 9” G-E Portables Jack Najork Service Techniques for Modular Circuits Harold Bernstein Mac’s Service Shop John T. Frye Handling FM-to-TV Interference George D. Philpott Service Industry News Antenna News
Test Equipment An Electrometer—A Very High Input Resistance V.T.V.M..Donn G. Shankland Low-Cost Scanning Generator A. V.H.F. Field-Strength Meter Adapter New Tube Tester Data
AMATEUR AND COMMUNICATIONS Shortened Rotary Beam Antennas for the Amateur.Herbert S. Brier, W9EGQ 72 Ham Communications from President’s Train 111
ELECTRONIC CONSTRUCTION AND THEORY Crystal Photocell Circuits Allan M. Ferres 58
DEPARTMENTS
Within the Industry What’s New in Radio Manufacturers’ Literature Technical Books Calendar of Events........----- Sales Aids
ZIFF-DAVIS PUBLISHING COMPANY WILLIAM B. ZIFF (1898-1953) FOUNDER Editorial and Executive Offices 366 Madison Ave., New York 17, N. Y.
yey Auit Bureau of VOLUME 57 . NUMBER 1 ‘Cireulations Copyright © 1956 by Ziff-Davis Publishing Company. All rights reserved.
SUBSCRIPTION Supvece. All communications conkeenion: subscriptions should be addressed to Circulation Pp 27 64 E. Lake » Chicago lll. Subscribers should allow at least four weeks for change of address. Include your old address as reli as new—enclosing, if possible, an address label from a recent issue of this magazine pect pry dg at Contributors are advised to retain a copy ted their manuscripts and illustrations. gee | gong oe should be jled to the New itorial Office and noes be accompanied by return postage. ag em tions will be handled no ili or their safety. copy is gto Sdaptations and revisions necessary meet the requirements of this pubiication, Payment covers ail author's, con- tributor’s, and a s Tights, title, one interest in and to the material accepted and will be made at TJ , are rates acceptance. All photos and drawings will be considered as part of the material purchased
RADIO & TELEVISION NEWS
# G. F. Beane, W. Virginia, was a truck driver. He took the DeVry Tech Training Program, and is now tape recorder en- gineer at Webcor Co.
Edward Hahn, Illinois. Now an electronics technician with Televiso, Inc. DeVry Tech training helped him prepare for his present position
Nick Barton, Ilinois, a DTI grad, now has his own busi- ness and tells us he is ‘‘liter- ally snowed with work.”
George D. Crouch, Califor- nia, was a retail store clerk. He took the DeVry Program, and today is in business for himself.
Get these Valuable
Facts.
EM CAN'T YOU2
O17
DeVRY TECH Will Tell You FREE
How You May Prepare At Home For
the Big-Opportunity Fields
TELEVISIO
RADIO - ELECTRONICS
TIRED OF THE SAME OLD JOB?
If you're under 55, you're not too old to consider a new type of job. If you feel the need of a change and want to look chead to the opportunities in Television-Radio-Electronics, mail the coupon below. Let DeVry Tech tell you about its industrial training program ... about the good pay jobs open to trained men. Find out if you are qualified for DeVry Tech training.
LEARN WITH REAL EQUIPMENT DeVry Tech puts tools and parts in your hands to build your own test equipment, loans you home training films to follow, explains problems in simple, down-to-earth language.
You need no previous technical experience to prepare at home or in our million-dollar Chicago Training Center. If you are between 17 and 55, send today for free booklet, free sample lesson and ad-
DEVRY TECHNICAL INSTITUTE
CHICAGO 41
ILLINOIS
DEFOREST’S TRAINING, INC.
January, 1957
A word of advice to Veterans
and Non-Veterans from
JACK DEMPSEY
“Let DeVry Tech give you an honest opinion
of the great opportunities in the electronics field. This school is now in its 25th year. I’ve known it a long time and, believe me, it makes no idle claims. It is in erested only in producing top-flight technicians. And in placing them, too. The DeVry Placement Service is in contact with some of the nation’s biggest businesses
.. it serves DeVry grad-
uates well. Why wait and wonder? Maybe
your future depends on sending in the
coupon below right now!”
MAIL TODAY FOR FREE FACTS
DeVRY TECHNICAL INSTITUTE 4141 Belmont Ave., Chicago 41, Iil., Dept. RN-1-N
Please give me free facts about the many opportunities in Tele- vision-Radio-Electronics, including the 3 publications, and how DTi may prepare me for my start in this billion-dollar field.
Name Age Please Print
Street Apt.
City Zone State
DeVry’s Canadian Training Center is at 580 Roselawn Avenue, Toronto 12, Ontario
ieee
AR 1 and 2 : BAe THE RADIART CORP,
MITTS
RADIO & TELEVISION NEWS
YOU GET ALL THIS NEWEST PRACTICAL EQUIPMENT
e Parts to build a modern TV set, including i we all tubes plus a large screen Picture Tube : RE e Parts to build a powerful Superhet Receiver, Sf oe standard broadcast and short wave
e Parts te conduct many experiments and build Continuity Checker, RF Ocillator, TV Circuits, Audio Oscillator, TRF Receiver, Signal Generator
e A Valuable Professional Multitester
YOUR NATIONAL SCHOOLS TELERAMA COURSE COVERS ALL 8 PHASES 1, TELEVISION, INCLUDING COLOR TV 5. PREPARATION FOR FCC LICENSE 2. RADIO, FM AND AM 6. AUTOMATION
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4. SOUND RECORDING AND Hi FIDELITY 8. COMMUNICATIONS
YOU ARE NEEDED IN THE TELEVISION-ELECTRONICS-RADIO INDUSTRY! — many other materials and services You can build a secure future for yourself if you get into Elec- — comers pitty 26 — —_ tronics NOW! Today’s shortage of trained technicians creates a ors Me wre Fg Bn Pr tremendous opportunities. National Schools Shop-Method trained YOU NEED for outstanding success technicians are in constant and growing demand for high-pay jobs in Electronics in Broadcasting and Communications, Electronic Research, Serv-
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Let National Schools, a Resident course. You can handle sales, servic- ining in Technical School for over 50 years ing, manufacturing, or make good t t aaageles. train you for today’s unlimited op- money in your own business. SEND y ; portunities in electronics! Our Shop FOR FACTS TODAY!
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students earn their entire tuition and more in Spare Time jobs we show them how to do while learning.
information oof Th
MEMBER
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TECHNICAL TRADE TRAINING SINCE 1905 LOS ANGELES 37, CALIFORNIA
é , 3 go FAST SERVICE — MAIL NOW TO OFFICE NEAREST YOU! r Radio-tle 0 F 2 al sample NATIONAL SCHOOLS, DEPT. RH-17 ‘ ait é PSS ' 7 0 CO » obligatio ! 4000 S. FIGUEROA ST. or 187 N. tA SALLE ST Beer P COUPO ' , ODA LOS ANGELES 37, CALIF. CHICAGO 1, ILL ! — ae Rush free TV-Radio “Opportunity” Book and sample
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January, 1957
ADDRESS
CITY. ZONE
= ae
Star Performer at a Modest Frice
E-V Model 927 Microphone. 1/4” wide x 1%” deep. 7,” long. Weight: 14 oz. with cable. Com- plete with desk stand and 5’ 0 NEES Oe $22.50 List.
Slecho Vor. Model 927 Crystal Microphone
No one—not even Electro-Voice —makesone microphone that does everything. Electro-Voice does make the closest thing to an all- purpose microphone on the mar- ket, the Model 927. For public address, call and paging systems, for dictating machines and home recorders, for amateur radio, for every general communications need.
Maximum versatility at a modest price. That’s what you get in the E-V Model 927. Designed primar- ily for hand use, it comes com- plete with a heavy die-cast slip-in stand for desk use. Attractive, streamlined microphone case of sturdy die-cast metal and plastic in metalustre medium gray. It’s omni-directional, has a 60 to 6,000 cps frequency response, can be used with any standard amplifier.
See your E-V Distributor or write for booklet N71,“"A B C’s of Microphones.”
Slecheyorcn
ELECTRO-VOICE, INC. ¢ BUCHANAN, MICHIGAN Canada: E-V of Canada Ltd., 1908 Avenue Road, Toronto, Ontario, Export: 13 East 40th Street, New York 16, U. S. A. Cables: ARLAB
Fn te RECORD.
RADIO & TELEVISION NEWS
LEE DE FOREST'S ALADDIN'S LAMP
T WAS just fifty years ago that.a
piece of wire bent back and forth in the form of a grid was first used as an element in a vacuum tube. The in- ventor was the renowned Lee De For- est, affectionately called the Father of Radio. Few men have contributed more towards the advancement of science than Lee De Forest. The tre- mendous importance of his discovery is reflected in the sales of TV and re- ceiving tubes for the first nine months of 1956 when over eight million TV picture tubes having a value of ap- proximately $147,000,000, plus over 347 million receiving tubes valued at near- ly $280,000,000 were sold.
De Forest was experimenting with an electrolytic detector for wireless signals in the year 1900. He was work- ing by the light of a Welsbach burner and noted that the light dimmed and brightened as his spark transmitter was operated. The illusion served its purpose well. De Forest realized that latent forces could be utilized in a Hertzian detector far better than any previously known device. His first commercial Audion appeared in 1906. De Forest, at the time, was exploring the behavior of a Bunsen burner flame using two platinum electrodes held close together in the flame together with an outside circuit comprising a battery and a telephone receiver. When one electrode was connected to an an- tenna and the other to ground, De Forest heard signals from a wireless telegraph transmitter in the telephone receiver. This was known as a “flame detector.” During the period 1903- 1905, De Forest considered the phe- nomenon known as the Edison effect and by 1904 he had outlined a plan of using a gas heated by an incandescent carbon filament in a partially exhaust- ed gas vessel as a wireless detector in place of the open flame. It was not until 1905 that De Forest had the op- portunity to prove that the same de- tector action, found in the vicinity of an incandescent platinum wire in the glass flame, also existed in gas sur- rounding the filament of an incan- descent lamp.
De Forest used small incandescent lamps for his experiment and intro- duced a second electrode which could be operated either hot or cold. De Forest called the battery used for lighting the filament the “A” battery and the other, for convenience, was called the “B” battery. This nomen- clature has been used ever since. De Forest had found that the influence of high frequency impulses could be im- pressed to better advantage on the conducting medium by adding a third
electrode. This new electrode was first applied to the outside of a cylindrical lamp bulb. De Forest’s patent of 1906 shows this progenitor of the third elec- trode. He concluded that if this were placed within the lamp, then the weak charges would be more effective in controlling the electronic current pass- ing between the filament and plate. He then tried two plates, one on either side of the filament. One was placed in the telephone circuit, and the other in the high frequency circuit connected to the antenna. It was in this circuit that De Forest first used a “C” bat- tery.
De Forest realized that if this third electrode were placed directly in the path of the current between the fila- ment and plate, he would obtain the maximum effect of the incoming im- pulses upon the current flow. He also realized that this electrode must not be in the form of a plate, but must be a perforated element which would per- mit the current to reach the anode. De Forest’s patent, filed January 1907, illustrated the preferred form which the idea promptly assumed.
During the summer of 1912, De For- est was working on problems of the Audions as amplifiers in cascade ar- rangements for telephone repeaters. It was then that he discovered that if the input or grid circuit was indirectly coupled with the output, or plate, in- ductance, the Audion would function as a generator of continuous alternat- ing currents. He demonstrated this type of circuit for the production of alternating currents of audible fre- quency and showed that weak high frequency currents could be generated by substituting radio frequency coils for the original iron-core coils. When the Audion was introduced as an oscil- lator in 1914, it replaced the arc in radiotelephony.
De Forest’s inventions and circuitry are too numerous to be covered in an editorial. Literally hundreds of wiring diagrams were developed, and experi- menters throughout the world under- took to improve the Audion’s perform- ance by designing circuits in which it could perform most capably. De For- est’s small piece of platinum wire and an additional battery had literally transformed the Fleming valve into a vacuum tube possessing unlimited ap- plications.
Electronics, as we know it today, would not have been possible were it not for the invention of the three ele- ment Audion. To Dr. Lee De Forest is due a debt of gratitude for his con- tributions to science and to our way fife? RES ee
RADIO & TELEVISION NEWS
Jan
January, 1957
ALLIED’S I957
value-packed 356-page CATALOG
the only COMPLETE catalog for everything in electronics
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4 RADIO & TELEVISION NEWS
GUIDE
®
AUTRONIC-EYE
TRAINING COURSES MEAN MORE BUSINESS FOR YOU!
Courses for experienced service technicians provide iatest repair information=-—enabie you to do the job faster and more efficiently.
Quick, accurate circuit diagnosis and repair to factory specifications boosts your profits. That’s why so many quali- fied auto technicians attend these Guide training courses
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Jumbo-size operational panel of Guide's Autronic- The Guide Lamp diploma, awarded only to those who Pong ocr hy pare St Getter Lelen, move successfully complete the course, is proof that you're equipped to give more and better service to more
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= gRRias « BLINKY MEANS Thirty modern GM Training Centers offer . ee g BUSINESS! newest equipment and latest service tech- , niques. There’s one nearby . . . no matter where you live. ah ate RADIO & TELEVISION NEWS
a
January, 1957 9
Can You Call a Man a “Failure” at Thirty?
Men who think that success is only a matter of “a few years’ are failures... however young they are!
How often have you heard some young man in business say, “I'll admit the job I have now isn’t much but, after all, I’m only in my twenties.”
Or: “Just about every executive in the company I work for is between 45 and 65. I have plenty of time to get ahead.”
This mistaken idea that success comes automatically with time is easy to understand. Promotions do come regularly and effortlessly to young men of promise. But the day arrives, often abruptly, when that promise must be fulfilled. Native ability and intelligence can carry a man only to the mid-way point in business—beyond that he must prove his capacity to justify a position of executive responsibility. That calls for a practical, working knowledge of business fundamentals.
The time to build that knowledge—to lay a solid groundwork for your future progress— is now ... now while time is still on your side. If you fail to recognize that fact, you'll know only struggling, skimping and regret when your earning power should be at its height.
FOR THE BUSINESS MAN WHO REFUSES TO STAGNATE
HH” the world is half asleep! what the qualifications of an execu- Men who could be making twice _ tive are in today’s competitive mar- their present salaries are coasting ket...what you must know to along, hoping for promotions but make $15,000, $20,000 or more a doing nothing to bring themselves year... what you must do to accu- forcefully to the attention of man- mulate this knowledge. agement. They’re wasting the most “Forging Ahead in Business” was fruitful years of their businesslives... written for ambitious men who seri- throwing away thousands of dollars ously want to get down to bed-rock they'll never be able to make up. in their thinking about their busi- If you want to discover how to ness future; there’s no charge for start to succeed while you're still the booklet because, frankly, we’ve young—if you want to avoid the never been able to set a price on it heartbreak of failure in later years that would reflect its true value. —send today for “Forging Ahead in Some men have found a fortune in Business”... one of the most prac- _its pages. If you feel that it’s meant tical and helpful booklets ever for you, simply fill out and return written on the problems of personal this coupon. Your complimentary advancement. You will discover copy will be mailed to you promptly.
—--- 5
ALEXANDER HAMILTON INSTITUTE Dept.514, 71 W. 23rd St., New York 10, N. Y. In Canada: 57 Bloor St. W., Toronto, Ontario, Canada
l I l I Please mail me, without cost, a copy of your 48-page book— | “FORGING AHEAD IN BUSINESS" i I !
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ALEXANDER HAMILTON INSTITUTE New Yokion.¥. L ee J
January, 1957 WW
YOU’LL START AND END EACH WORKING DAY WITH THE POWER-LAB
For the first time in the industry, one instrument takes the place of more than 11 pieces of equip- ment and makes you wonder why no one ever did this before . . . the most useful, often used, test device in your shop.
Here’s the story . . . now, you can get all this COMPLETE IN ONE KIT (kit or wired):
* A BATTERY ELIMINATOR
* A BATTERY. CHARGER
* A HIGH CURRENT LINE VOLTAGE VARIAC * AN AC LINE VOLTAGE METER
* AN AC LINE AMMETER
* AN AC LINE WATTMETER
* AN AC LINE ISOLATION TRANSFORMER
* A LOW VOLTAGE, HIGH CURRENT AC SUPPLY * A DC LINE VOLTAGE VARIABLE SUPPLY
* A DC HIGH CURRENT AMMETER
* AN AC BIAS BOX
When you buy POWER-LAB by Precise, you get all the advantages of owning a battery eliminator for servicing auto radios (even signal seekers), an AC-DC Converter, a supply for transistor sets, AND OF MAINTAINING A CONSTANT 115 volts in checking on TV set variations. You can even run the set down to 105 volts for testing for hori- zontal jitter and back up to 125 volts for high voltage breakdown, thereby eliminating the cause of many call-backs due to arcing .. . PLUS
There's NO OTHER INSTRUMENT LIKE THE POWER-LAB ON THE MARKET. Here again, Precise engineering is proud to be the first to supply a need that has too long existed in the service trade.
Your Distributor will be proud to show you THE POWER - LAB
Prices slightly higher in the West. Prices and specifications subject to change without notice.
WRITE FOR CATALOG RN-1-7
.. PLUS... PLUS ... the 101 uses you'll find each day for POWER-LAB versatility.
Just look at these specs .. . the switches used are more than ample to carry related loads re- quired and the quality of every component is EXCELLENT. You could easily pay three to four times the price of the POWER-LAB for the equip- ment to perform only a few of the functions of the POWER-LAB!
, —- ) ; ? precise DEVELOPMENT CORP. oceansibe, New YorK, U.S.A
MODEL 711 (100 Waits of Isolation)
ae
MODEL 713 (300 Watts of Isolation)
BENCH & SHOP
711K — $49.95 9 :
ws ai
711W-- $64.95 wired
713W— $79.95 wired ALL SPECS BELOW ARE FOR MOD. 711 ANG 713 UNLESS OTHERWISE SPECIFIED
VOLTS MAXIMUM | CONTINUOUS | fim Low Voltage DC | 2 ranges 0-15v Full Wave 20 amps* | 10 amps* 0-30v Full Wave Bridge} 20 amps* | 10 amps* | Low Voltage AC 0-24v 20 amps High Voltage AC | No Isolation 90-140 volts 20amps | 10 amps 2000 watts | 1000 watts im High Voltage AC | Model 713 with Isolation 3 amps 90-140 volts 300 watts High Voltage AC | Model 711 with Isolation 1 amp | 90-140 volts 100 watts : High Voltage DC 110-180 volts lamp** |.075 amp** |
*Depending on voltage.
**May be increased up to 10 amperes at additional cost.
SEE THE MANY MORE PRECISE INSTRUMENTS AND PROBES AT YOUR DISTRIBUTOR TODAY!
OPPORTUNITY FOR YOU!
I) PREPARE AT HOME FOR A
t Handling Materials
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Get in on the Ground Floor of this
Fast-Moaving
Wart o betie: job? . . . more money? . . . befter working conditions? These are the things that ca come to « man when he has a skill to offer . . . when that skill is in a newer field where opportunities often lead to well- paying itions. Such a field is the Electronic applications te AUTOMATION — and what a field! Many plents, large and small, in various parts of the country are looking for ways of using auto- matic electronic control equipment to help turn out a better product and at jower cost. This equipment must be designed, installed and maintained — calling for well trained men. That’s where YOU come in! fou need no special technical experience .. . no previous k of Automation Electronics ... to prepare for a that can be bright and more secure. For now there is a proved way to get this important know-how. Mail coupon for com- plete detail:. Men 17 to 55 preferred.
*WHAT IS AUTOMATION ELECTRONICS? Simply stated, this refers to the marvelous elec- tronic controls that will help regulate the much talked about “automatic factory” —as well as other amazing aviomatic equipment in plants, offices and elsewhere. It is a gateway to some of the most desirable opportunities in the amazing, newer
eerie Seatemescos FOREMOST ELECTRONICS
DEVRY TECHNICAL INSTITUTE
CHICAGO 41, ILLINOIS
DEFOREST’S TRAINING, INC.
January, 1957
Field Recording and billing
A New Training Program! s As one of the leading organizations of / its kind, the DeVry Technical Institute hes years of experience in teaching Electronics, Television and Radio. So it : only natural for this training institute P develop a new program to prepare good jobs in instrumentation — as in the design, installation and intenance of Electronic controls —
as applied to Automation.
Foliowing the same proved method wsed to train thousands of other men, eo
oe valuable practical experience
actual electronic equipment. You
also receive well-ilivstrated texts and
home training advantage! To top that off, DT! provides actual employment help when you have completed the training—all of which can open the way to many new and exciting opportunities.
mnt National Home Study Council
MAIL THIS COUPON TODAY!
DeVRY TECHNICAL INSTITUTE, Dept. RN-1A-N 4141 Belmont Avenue, Chicago 41, Ill.
1 would like a FREE copy of your booklet, Automation and YOU.” Also further information about the newer Electronic opportunities in AUTO- MATION, and facts on how you may help me to prepare.
Age =.
Apt.
Zone State DeVry’s Canadian Training Center is at 580 Roselawn Avenue, Toronto 12, Ontario
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ew ee OO He
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R L Peake eR I N ADF. R A Dt O RADIO & TELEVISION NEWS
No antennas ever made can match the perform- ance and sales appeal of these outstanding Channel Master models.
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i f¢
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ontrol center for a nation
network of automated factories
Think of it . . . Completely automatic factories, hun- dreds of miles apart, all operated by a single Remington Rand Univac® computing system. Flow of materials, processing, quality control, packaging, even market analysis, controlled from the electronic “‘brain center’’ . .. control so complete that when a shift in the wind changes the draft of a chimney at a distant plant, the computer corrects the firing of a boiler.
Far fetched? Not at Univac. The Univac team of scientists, engineers and technicians has already de- signed the completely automatic factory. They have built a computer (Univac Scientific) capable of remote control of ten to a hundred factories. The next step— central control of chains of automated plants—will completely revolutionize American industry.
This is the kind of challenge that awaits you at Univac. As a Univac engineer or technician you'll find top salaries, excellent working conditions and opportunities unlimited—unlimited as the future of Univac itself.
®Reg. U.S. Pat. Off.
tse Latha ee,
IMMEDIATE OPENINGS FOR: FIELD LOCATION ENGINEERS with a college degree in a scien-
tific or engineering field and experience in electronics. Extensive electronic background may substitute for some college. Many opportunities for rapid advancement.
FIELD LOCATION TECHNICIANS with technical school back- ground and preferably some experience in electronics, These positions can lead to full engineering responsibility.
Send Complete Resumé to:
Hemington Bland. Univac. DIVISION OF SPERRY RAND CORPORATION MR. PHIL WILSON Dept. $J-9
1902 W. MINNEHAHA AVENUE, ST. PAUL W4, MINNESOTA
£ A
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to phomo cartridge and tieedle market with vd
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\
eae CAR TRIOGE WIEH ?
JEWELEP* PLAYING TIPS)
CUT INVENTORY COSTS REPLACE CARTRIDGE we AND NEEDLE IN SECONDS
Power-Point Replaces over 90% (Just Slip Out— Slip In)
of All Popular Phono Cartridges
E-V Power-Point actually gives you more working Four Power-Point Types, Three Mounting capital by cutting, drastically, the number of differ- each $3.95 list Mechanisms ent cartridges and different needles “or need in stock Model 51-1 (Red): twol-milsap- (A> Model PFT-1 Power- to do an adequate replacement business. Power- ‘rao \x — Print Fj
phire tips. (T= Point Fixed Mount, Point alone replaces over 90% of all popular phono oy 50c list. cartridges. You save valuable time, troublesome Model 52-2 (Green): two 2-mil 5 service calls . . . you can replace Power-Point in less sapphire tips. « > nv 4 Z a time than it takes to read this sentence! Remember & mit “RR CSP too, almost a million Power-Points are now in use, eather co two 3-mil AQ Mount, $1.00 list. and the number is growing fast. Additional mil- Model PT-2 Power-
lions will be demanded by the replacement market! Model 56 (Blue) : turnover mount- Gr Point Turnunder ed 1-mil and 3-mil sapphire tips VES Mount, $1.00 list.
What is Power-Point?
A nylon-encased unit combining ceramic cartridge and two jeweled* playing tips. A Power-Point cartridge can be changed in seconds, replaces virtually all popular phono cartridges, costs less than two needles alone. It has low inertia, superior tracking ability, wide range, low distortion, minimum needle noise and record wear. It is non-inductive, hum-free, unaffected by moisture or temper- ature. It actuates all changer mechanisms.
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Slecho Voice
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Send me complete information about Electro- Voice ( Power- Point cartridges, sales-aids and display.
Company , Address City
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An intrstng exprmnt in spch
Some day your voice may travel by a sort of electronic “shorthand” when you tele- phone. Bell Laboratories scientists are ex- perimenting with a technique in which a sample is snipped off a speech sound—just enough to identify it—and sent by wire to a receiver which rebuilds the original sound. Thus voices can be sent by means of fewer signals. More voices may economically share the wires.
This is but one of many transmission tech- niques that Laboratories scientists are explor- ing in their search for ways to make Bell System wire and radio channels serve you more efficiently. It is another example of the Bell Telephone Laboratories research that keeps your telephone the most advanced on earth. The oscilloscope traces at right show how the shorthand technique works.
BELL TELEPHONE LABORATORIES
World center of communications research
Largest industrial laboratory in the United States
18
“
Vibrations of the sound “or” in the word “four.” Pattern represents nine of the “pitch periods” which originate in puffs of air from the larynx when a word is spoken.
An electronic sampling of the “or” sound. One “pitch period” in three has been selected for transmission. This permits great naturalness when voice is rebuilt. Intelligible speech could be sent through a 1 in6 sampling.
The selected samples are “stretched” for transmission. They travel in a narrower frequency band than complete sound.
Using the stretched sample as a model, the receiver restores original frequency. In all speech, sounds are intoned much longer than is needed for recognition—even by the human ear. Electronic machines perform recognition far faster than the ear.
The receiver fills in gaps between samples, recreating total original sound. Under new system, three or four voices could travel at once over a pair of wires which now carries only one—and come out clearly at the end!
RADIO & TELEVISION NEWS
N.R.1. Train Chief Technicia Avto Radios, P. SHIP AND H Operator. POL MENT RADIC Dispatcher, Airy mitter Design Te
Thanks N.|
~~ eet
Engineer +t
eck -i- i ak. ae
You Can Train at Home for Good Pay Jobs in
RADIO -TELEVISION
Fast Growing Industry Offers Good Pay, Security, Bright Future
Training PLUS OPPORTUNITY is theideal com- bination for success. Today’s OPPORTUNITY field is Radio-Television. Over 125 million home Radios plus 30 million sets in cars and 40,000,000 Television sets mean big money, opportunity for trained Radio-Television Technicians. More than 4,000 Radio and TV Broadcasting stations offer interesting and important positions for techni- cians, operators. Color Television, portable TV “asets, Hi-Fi, other developments assure future b growth. Radio, Television are both growing. Need J. E. SMITH trained technicians i is increasing! Founder
Find Out What Oldest and Largest Home Study Radio-Television School Offers You
Since 1914—for more than 40 years—N.R.I. has been training ambitious men at home in spare time for Radio-TV. Thousands of successful graduates say N. "Rl? ’*s 50-50 training method is a fast, easy, effective way to higher earnings, desirable jobs. Carefully planned experiments and practice with equipment supplied free of extra charge, bring basic principles, techniques to life right in your own home. Find out what dependable training can do for you.
You Learn by Doing—Get Practical Experience with Kits N.R. I. Sends
a
, . Add to Your Income Starting Soon Nothing takes the place of practical experience.
k $ $ k ry + lk _ stam Course ee =
* - adio Receiver and Vacuum Tube Volt- ee Ma e 10 15 a Wee Extra a shown below. Use them to make tests, seme FixingSetsinYourSpareTime conduct experi
experience. All equipment yours to eep.
Soon after enrolling, many N.R.I. students ® start earning extra money fixing neighbors’ » radio sets. Many earn enough extra to pay \) entire cost of course and provide capital to start their own full time Radio-TV business y after getting N.R.I. Diploma. If you want a | job vith a future, find out how you can train | at home for Radio-Television. Mail Postage Free postcard for Sample Lesson. See how ea practical it is to learn at home. Get 64-Page ™ + 1] Catalog, too. See equipment you get, out- m lef tt z ' ee of ny ng: about, opportanianes in coe s this growing field. Prices of N.R.I. re 5 Oth $i d
op ! > are low, terms easy. ee er i e|
N.R.I. Training leads to good pay jobs like these. BROADCASTING: me ee ees ees es «COC CUT OUT AND MAIL CARD NOW 3 o=_ ==
Chief Technician, Chief Operator, Remote Control Operator. SERVICING: Home and
Auto Radios, P. A. Systems, Television Receivers, Electronic Controls, FM Radios, Hi-Fi. 1. SAMP LESSON ° NO STAMP NEEDED! SHIP AND HARBOR RADIO: Chief Operator, Assistant Operator, eget donot
Operator, POLICE RADIO: Transmitter Operator, Receiver Serviceman. GOVE . ‘we PAY POSTAGE MENT RADIO: Operator in Army, Navy, Marine Corps, Coast Guard, Forestry ma
Dispatcher, Airways Radio Operator. IN RADIO PLANTS: esign Assistant, Trans- i AND CATALOG
mitter Desig: Technician ... AND MANY OTHERS. "lity /
N-R.I. TRAINED THESE MEN 'W:Ye} ¢ 7 Md.) 4 =I
Thanks N.R.1I. for Good Start QuitJobto Start Business ‘ 7: j This cara entitles you to Actual Lesson on Servicing, shows
Right now I am doing I decided to quit nati how you learn Radio-Television at ome. You'll also receive
spare-time repairs on job and do TV work full ’ ’ time. I love my work i 64-Page Catalog.
Radios and Television. : as gd doing all right Going into full time a financially.’ | NATIONAL RADIO INSTITUTE, Dept. E servicing soon,’’ C, HIG- i oT KLINE, C PAE W. shington 9, D. C.
GINS, Waltham, Mass. j Ohio . ‘ lease mail me the FREE sample lesson and 64-Page
Catalog. (No Salesman will call.)
Engineer vith Station WHPE N.R.1. Star°ed His Way up i s: ( ' ,
“— operated a succ-ssful “I was a cab driver earn- Name ____. _— Age
Radio repair shop. Then ing $35 a \.eek. Then I i
I got dg | with WPAQ enrolled with N.R.I. g Address........
enc tow 5 am an eng ' Now testerwith TV mak-
Dias ae \ ‘ » ae ere
ae Set ar at. Som er.” J. H. SHEPHERD, g ©1Y------- Zone State
W. WORKMAN, High y»
Point, N. C. a Bloomington, Ind. Approved Member, National Home Study Council
Practice Servicing- Communications with Kits of Parts N.R.I. Sends
ht
YOU BUILD AC-DC Superhet Receiver
N.R.I. Servicing Course includes all needed parts. By introducing defects you get actual servicing experience practicing with this =) modern receiver. ~~ Learn-by-doing.
YOU BUILD Signal Generator quency amplifiers, practice aligning ? Make tests,
9 You build this Signal Generator.
fe = Learn how to compensate high fre-
¥ d : typical I.F. amplifiers in receiver ‘ : circuits. conduct ex-
periments.
i | | YOU BUILD YOU BUILD Vacuum Tube Broadcasting Transmitter Voltmeter an ges Es él 1 Use it to earn extra cash part of N.R.I. Communications Course ones an np ed —
ae build this low power Transmitter, learn commercial broadcasting operators’ methods, procedures. Train for your FCC ’ Commercial Operator’s License. i “
bry
ou learn from
-R.
understand texts.
I.’s easy-to-
Radio-Television Can Give You a Good Job with a Future
N.R.I. Graduates do Important Work — Get Important Pay
Paid for Instruments
Chief Engineer Has Own Radio-TV with Station out of Earnings Business “TI am Chief Engineer of “I am doing very well in “We have an appliance andan, spare time TV and Radio. store with our Radio and
Station KGCU in N I also have my own spare time business serv- icing high frequency, two-
Sometimes have three T'V jobs waiting and also fix car Radios for garages. I
way communications sys- paid for instruments out of helped get me a to tems.” & —, Bis- a %,~ F. re job.” W. * WEI marck, New airfax, S
TV servicing and get TV repairs. During my Army service, N.R.I. a
NER,
> See Other Side “aK
FIRST CLASS Permit No. 20-R (Sec. 34.9, P. L. & R.) Washington, D.C.
BUSINESS REPLY CARD
No Postage Stamp Necessary If Mailed In The United States
POSTAGE WILL BE PAID BY
NATIONAL RADIO INSTITUTE 16th and U Sts., N. W. Washington 9, D. C.
' Radio, n M expanding—making more jobs, greater opportunity.
Here is a line of work that people respect—a vocation where you ean advance, win a place for yourself, earn pay and gain much personal satisfaction in what you are able to do. And you can learn at home in your spare time. Smart fellows everywhere are using their spare time to develop new knowledge, new skills. They know it is the trained man who gets ahead, gets the better job, drives the better car, is respected for what he knows and can do.
Be a Skilled Technician
The technical man is looked up to. He should be. He does important work, gets good pay for it. Radio-Television offers that kind of work. There are more than 40 million Televisions, 150 million home
and auto Radios. Millions more are sold each year. There are splendid opportunities for the man well trained in io-Television Servicing or Broadcasting. Micro-Wave Relay, Aviation and -Police wo-Way Communications for buses, taxis, trucks, etc. are
You Can Train in Spare Time
ag your job until you’re ready for a better one. Learn at home. N.R.I. Courses are planned for men who can study only during spare time. You get many kits to build equipment, get practical experience. You work on circuits common to both Radio and TV. Equipment you build “brings to life’”’ thin > learn in N.R.I.’s easy-to-understand texts. Experienced N R. instructors, techni- cians, specialists devote full time to making sure you get the best and simplest Radio-TV training. Train as fast or as slow as you like.
Tested Way To Better Pay
Wie Training is practical, thorough. You get the benefit ot N.R.I.’s 40 years experience training men for success in Radio- Tele f
elevision. Most successful N.R.I. men start without any knowledge Radio, many without a high school education. Find out what Radio-Television training can mean to you. Make a decisive move today toward becoming one of that select ag Radio-TV Technician. Send for Actual Lesson and 64- Catalog, both FREE. NATIONAL RADIO INSTITUTE, Dept. E, Washington, D.C.
SAMPLE LESSON AND
CATALOG Lg BP e i
BOTH
CUT OUT AND MAIL POSTAGE-FREE CARD
for the expanding
independent service-dealer
Moré and more independent service-dealers are strengthening their competitive position by broadening their activities. They are adding to radio and television service: Marine, mobile and citizen radio .. . sound systems . . . industrial equipment . . . special electronic devices . . . etc.
These forward-looking independent service- dealers are discovering expanded lines of CBS in- dustrial tubes and semiconductors ready to help
Reliable products through Advanced-Engineering
Jenuary, 1957
them in their profitable new fields. New PA-5 and PA-17 reference guides describe respec- tively over 200 CBS industrial receiving, power and special-purpose tubes . . . and a wide line of CBS crystal diodes, transistors and silicon power rectifiers.
Both guides are free . . . from CBS Tube distributors or direct. Just ask for Bulletins PA-5 and PA-17.
1 tubes - semiconductors
CBS-HYTRON Danvers, Messachusetts A Division of Columbia Broadcasting System, Inc. 21
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TUNG-SOL mokes All-Glass Sealed Beam Lamps, Miniature Lomps, Signal Fleshers, Picture Tubes, Radio, TY and Special Purpose Electron Tubes and Semiconductor
* Presenting latest information on the Radio Industry.
By RADIO & TELEVISION NEWS' WASHINGTON EDITOR
THE MAMMOTH TY very-high—ultra- high allocation problem, that scores of experts have been trying to resolve for years, now has been formally turned over to a TV allocation study organ- ization, who will attempt to develop a body of facts that can be used by the FCC to determine the soundest ap- proach to channel! allocations.
The group, it was said, will not be- come involved in product research or in the economic and sociological as- pects of the allocation situation. Studies of these factors will be as- signed to other special committees composed of engineering specialists and marketing experts.
All members of all groups, however, will base their analyses on the basic conditions outlined in the crash re- search notice issued by the Commis- sion in the early fall of ’56.
CLOSED-CIRCUIT TV, featuring pro- grams ranging from native folk dances to demonstrations of the use of color TV in medical science, is having a ter- rific impact on visitors to the United States central exhibits at international trade fairs now being staged in various parts of the world.
In Afghanistan, experiencing its first look at TV, His Majesty, Mohammed Zahir Shah, participated in the first telecast in the history of the country during his visit to the U. S. Pavilion in Kabul. Accompanied by an entou- rage of 300, including members of the
Royal Family, the King saw himself on the TV eye, which proved to be one of the hits of the exhibit. Six monitors located at strategic spots through the show were crowded constantly as Af- ghans and visitors delighted in seeing themselves and friends in action.
A similar TV eye is currently fasci- nating large turnouts at the Ameri- can exhibit in Izmir, Turkey. More elaborate TV closed circuits, operating from attractive glass-enclosed studios, have been installed at our exhibits in Stockholm, Damascus, Salonika, Vien- na, and Zagreb. At these fairs, viewers can see performances by local singers, instrumentalists, dancers, puppeteers, comedians, and dramatic actors, as well as demonstrations of a variety of prod- ucts and devices which are on view in the American pavilion. Do-it-yourself demonstrations, the workings of farm implements and household appliances, etc., are shown by way of monitors. Fairgoers are also able to see step-by- step techniques of homesewing from a pattern stage to machine operation and finally the modeling of finished house dresses.
The largest of the closed-circuit TV operations are in the Damascus and Stockholm exhibit areas. Erected in the center of a U-shaped building, the Damascus studio permits fair visitors to watch programming in the court- yard and on fifteen monitors scattered throughout the zone. Two cameras and six technicians man the operations.
NEW TV GRANTS SINCE FREEZE LIFT
Continuing the listing of construction permits granted by FCC since lifting of freeze. Additional stations will be carried next month.
STATE CITY CALL
CHANNEL FREQUENCY POWER*
Walla Walla Casper Arlington
Washington Wyoming Virginia
8 180-186 3.04 2 54-60 -208 20 506-512 -676
New Call Letter Assignments
STATE CITY CALL
CHANNEL FREQUENCY
Palm Beach WPTV Ashland New Orleans
Coos Bay Alpine
Florida Kentucky Louisiana
Oregon Texas
KOOS-TV
(Formerly WJNO-TV) WALN.TV 59 (Formerly WPTV) WWEz.TV 32
KAMT-TV
5 76-82
16 12
*ERP~ (effective radiated power, kw.)
RADIO & TELEVISION NEWS
JERROLD Introduces
TRAP-EASE*
Revolutionary New TV
Filter Knocks Out Adjacent Channel Interference... Opens New Sales Market For The Television Trade !
This tunable ‘‘deep notch” antenna trap (greater than 50 db) permits TV viewers to remove “beat” or “herring- bone” patterns caused by strong adjacent channel sound or video carriers. Permits clear reception of even weak
distant stations.
RECEIVER 1.F. RESPONSE '
TRAP-EASE SELLS ITSELF
Let the amazing perform- ance of the Jerrold Trap- Ease do its own selling. One demonstration and the Trap-Ease sells itself with the greatest of ease. Simple to demonstrate either in your store—or in the customer’s home.
In case shown Re- ceiver AGC is held down by a strong ad- jacent channel sound carrier, This lowers receiver gain and prevents proper re- ception of the desired channel. “Beat” or “Herringbone’’ pat- tern is predominant on the screen.
channels.
BRINGS IN PICTURES FROM OUT OF NOWHERE! TRAP-EASE
rs Mc——>
RECEIVER I.F. RESPO
NSE 1.5 Mc
Before TRAP-EASE is Installed After TRAP-EASE is Installed
The adjacent sound carrier has been sup- pressed by some 50 db, which: (1) En- ables the signal level of the desired channel to control the AGC action of the receiver. (2) Completely re- moves the ‘“beat’’, leaving a clear, strong picture.
MONEY
BACK GUARANTEE
Never before a TV accessory that achieves such startling results. Contact your Jerrold distributor today for details on the complete
sales promotion package available to you.
TWO MODELS AVAILABLE
Low Trap-Ease (Model H
91) covers Channels 2 to 6. High Trap-Ease (Model HQ-92) covers Channels 7 to 13.
JERROLD ELECTRONICS CORPORATION 23rd and Chestnut Streets @ Philadelphia 3, Penna.
*@Jerrold Electronics Deep Notch Adjacent Channel Trap
Works with any TV receiver and any 300 ohm antenna that would normally bring in pictures from the distant stations if the interfering adjacent channel was not on the air. Does not affect reception of regularly viewed
EASILY INSTALLED
Simply connect the Trap- Ease in series with the antenna lead-in and mount on rear or top of TV receiver. Handsome contemporary design and soft color tones of the unit harmonize with today’s modern or tradi- tional cabinet decor.
Here Is The Best Value Ever Offered In An Electrical Measuring Instrument...
METER PROTECTION The meter movement is
protected up to 1000 times \\ Wl overload by rectifier network. 5 5 ie h
A.C.-D.C. V.0.M.
ONLY THE PHAOSTRON “555A” V.0.M. (VOLT OHM MILLIAMMETER) MEASURES A: C. and D.C. CURRENT and VOLTAGE AS WELL AS RESIST- ~ ANCE AND HAS ALL THESE FEATURES:
@ Unbreakable Metal @ Easy-to-Read, Large Other Fine Case of Highly 4-Color Scales Phacstron Products Polished Chrome * @ 43 Unduplicoted Ranges MODEL “777”—Vacuum Tube Volt- @ Separate Range and @ Only 2 jacks meter...42 unduplicated ranges Function Switches @3% D.C....4% A.C. with permanent accuracy-3% D.C.,
eS 5% A.C, ®@ Anti Magnetic Shielding Permanent Accuracy nh om Pande Witneames.
2%2",342",4%2",6"...0ll shielded by their metal cases from stray
ACCESSORIES AVAILABLE magnetic fields. 2%" and 312” Genvine Leather Carrying Case $7.95 cr swol cvailable in round or 4 squore face. Panel Mounting Adapter $1.59 pombams renebanéity . INSTRUMENT...with double probe outlets and full overload protection.
” rm ‘ RUGGEDIZED AND SEALED BEERS coating $ 50 PANEL INSTRUMENTS... ovailable complete with probes ond batteries tat in 1%” (Square Bezel) and 2%”,
ot your Parts Distributor 3%", 44," Round Bezel models in AC, DC or Null indicators.
Write today for full! details or ask your dealer
PHAOSTRON INSTRUMENT AND ELECTRONIC COMPANY
151 Pasadena Avenue, South Pasadena, California
According to reports, hourly, crowds of several thousands collect in and around the pavilion at night to watch well-known Syrian. performers put on shows. The big hit of the program is the double-or-nothing quiz show which had to be expanded from a half hour to a full hour to satisfy audience in- terest. Every twenty minutes, a Syrian announcer interrupts the program to explain how the television circuit op- erates. In Sweden, there ‘are thirteen monitors in operatiorr.
The Vienna exhibit consists of a sim- ulated fully equipped hospital oper- ating room. An operation performed on a medical mannequin is transmitted via a miniature camera mounted in the operating light. In similar fashion, minute details of dental surgery are shown on color-TV monitors. Another feature of the display is built around a color-TV microrzope through which images are magnified for analysis. Transmission in color displays the nec- essary color differentiation in cells and tissues. Demonstrators, playing the roles of surgeons, are provided with throat or hand microphones so that their commentaries. may be heard by the public. ;
In addition, to television, our elec- tronics industry is represented in the foreign exhibits by a wide variety of radios, including those transistorized and powered by the sun, those small enough to place in the palm of a hand and table models; tape recorders and oscilloscopes; high-fidelity phono equip- ment, etc. At Izmir, there is a graphic display of the history of broadcasting from the crystal.set era to the newly- developed solar-battery radios.
Record. shops gaily decorated with album jackets have been installed in show quarters in Stockholm, Zagreb and Bari, Italy. In Bari, there’s a large exhibit of hi-fi equipment in op- eration in a colorful garden’ adjacent to the exhibition building. Records can be played in eight glass-enclosed booths. There are eight tape machines in operation at other fairs which vis- itors can use to record and play back their own voices.
A BOLD BID for channel 2 to serve as a mobile band appeared in a recent petition to the FCC entered by the American Trucking Association; the Commission was asked to reallocate that channel for fixed scatter service.
In commenting on its request, the association said that the motor carrier industry must now share three of the 12 frequencies in the 25-50 megacycle band with passenger carriers. All of these frequencies, they said, are se- verely congested and conditions are getting worse every day.
The ATA petition pointed out that the “. . . Commissidn’s decision not to reduce channel separations in the 25- 50 band, which offered the best pros- pect for immediate satisfaction of the motor carrier industry’s need for addi- tional assignments in the very-high band will . . . adversely affect the ra-
(Continued on page 132) RADIO & TELEVISION NEWS
" RADIO-FM-TV TECHNICIAN TRAINING
FM-TV TECHNICIAN TRAINING
Sylvania Now Sponsoring RTITA’s Color Technician Course One of the nation’s largest electronics manufacturers and marketers Sylvania Electric
vets Ine. in ite continuing effort to cooperate with inde-
Available >» “Authorioed Syl- vania Dea
My School fully approved to train Veterans under J new Korean G. 1. Bill. Don’t lose your school bene-
fits by waiting too long. Write discharge date on i coupon.
Radio-Television Training Association
January, 1957
| MAIL THIS COUPON TODAY!
aa io Mr. Leonard C. lene, President RADIO-TELEVISION TRAINING ASSOCIATION
Dept. RT-1D, 52 East 19th Street, New York 3, N. Y.
Dear Mr. Lone: Send. me your NEW FREE BOOK, FREE SAMPLE LESSON thot will show me how | can moke TOP MONEY IN TELEVISION. | understand | am under no obligation.
(PLEASE PRINT PLAINLY)
City. (D Color TV Technician Course (O Redic-FM-TV Technicien Course ( FM-TV Technician Course C TV Studio Technician Course Bee ee eee ee ee ee
How far
can you go
in electronics
without
a degree?
2 years ago, degreeless Bill Miles had reached a blind alley in his career. Yet today, with IBM, he's actually supervis- ing engineers in America's biggest elec- tronics project. Here's how this technician broke through the “education barrier.”’
“Training and local assignments,” recalls Bill Miles, “were what caught my eye when I saw an IBM ad in 1955. So I in- vestigated. Now here I am with an ad- vanced electronics education under my belt—and responsibility as a Group Super- visor in Project Sage. I work on the world’s largest and most advanced compuier. I live in my home town. And my future in the company is what I make it. Yet only 2 years ago, I thought I’d gone as far as a technician ever could!’
Becomes radar technician
Bill’s background is typical of thousands of capable, ambitious technicians who never acquired a formal engineering degree. His interest in electronics, aroused in Camden, New Jersey, high school, was nourished by a 8-year stint as Aviation Radar Tech- nician in the Navy’s “Black Cat” air-sea rescue squadron.
Takes night courses
Discharged in 1946, Bill married a girl he’d known in high school. During the
32-year-old Bill Miles talks frankly about the technicians’ biggest problem
next 9 years, Bill was teacher in a radio-TV institute, TV service man, TV company technician, and chief supervisory TV tech- nician. All the while he pursued an engi- neering education at night. But growing family responsibilities made it more and more difficult.
Finds doors barred
However, feeling he was equipped for greater responsibility, Bill, now 30, in- vestigated several companies but found that, while they liked his abilities, his lack of degree barred the door to any significant future advancement.
Enters (BM school
In May 1955, when he moved his family to Kingston, New York, and started at IBM, Bill wasn’t quite sure what to expect. The 9-month training course—valued at $10,000 per man—had been the big mag- net for him. He hoped the future would match his expectations.
Meets head of school
“Sixty of us started school at IBM, at- tending class 8 hours a day. The course consisted of about 20 subjects, mostly dealing with computer circuits and units,
and maintenance techniques. The teaching was adult, superb. After the first 20 weeks, our living expense allowance, over and above salary, rose to $59.50 a week. We kept our own grades, and every 6 weeks when we reviewed them with the instruc- tors, they asked us for ways to improve the course. I expected a casual ‘hello’ when I met the Division Manager of Education, but he talked to me for an hour about myself and my interests. The real concern IBM hzs for you as an individual, both before and after they hire you, is undoubtedly one reason why we all began to take a lot of pride in this outfit.”
Joins home-town computer site
Bill had joined IBM as a Field Systems Engineer. After graduation, when 10 of his classmates were immediately promoted to specialized assignments, Bill was assigned to a computer site near his home in Mt. Holly, New Jersey, with IRM paying his moving expenses. For the first two months he helped install the SAGE computer, an impe:tant link in America’s air defense. Ultimately, such computers will ring Amer- ica’s entire air defense perimeter. Looking back, Bill notes, “I’ll admit the work was laborious and difficult, but still I have a sense of great accomplishment. Together we all helped create something of value from almost nothing.”
RADIO & TELEVISION NEWS
World’s largest computer
“The computer is probably the largest one in the world, with over a million compo- nents. Flattened out, it would probably fill a ball field. The computer analyzes radar data on every object in the sky. Then it checks each object against available traffic information and identifies it as either friendly or hostile. It can make sugges- tions, but it can’t send a Nike missile against what it thinks is a ‘baddie.’ Only airmen can make that decision.”
Bill gets $10,000 computer education at IBM Kingston
Supervises fifteen
Recently promoted to Group Supervisor, Bill now directs an entire shift of 15 men, reporting to a Group Manager. His job: to maintain the computer in combat readi- ness. “I have to be familiar with the entire system. I rely on two types of specialists to help me: computer units men who are specialists in certain areas; systems engi- neers for the over-all computer.”
Miles does diagnostic programming on the Maintenance Console of the Sage Computer
January, 1957
Miles nails down problem with Site Manager R. Schimmel
Buys house, car
Bill has bought a 7-room house-in Mt. Holly. When not busy with his son and twin daughters, he likes to bowl. He drives a ’56 automobile. He’s enjoying the good life, and expects it to get even better. His employee benefits alone represent a cash value of many hundred dollars a year. He expects the IB M-sponsored General Educa- tion Program will prepare him for higher management responsibilities. Later, Bill’s manager said, “‘He’s currently assuming the responsibilities of an electrical engi- neer.”’
But the question remains: Is Bill really an engineer?
The “professional” engineer
“No, I certainly don’t consider myself a ‘professional’ engineer, qualified to design machines, for instance. But the point is, I’m doing work ordinarily done by engi- neers . . . work usually denied to men without a degree.”
IBM upgrades technicians
Could he do this elsewhere? “Of all the companies I know, IBM appears to be one of the few upgrading the technician to the level of engineering responsibility. Fortu- nately for me, IBM had the imagination to get men without degrees and encourage them to rise in responsibility and income to the level of their native talents ... not what their formal education dictates.”
“Student” Bill Miles diagrams computer circuit
Both titles gain
Is this a sign that the educational system is wrong? “Not at all,”” answers Bill Miles. “A Doctor’s, a Master’s, a B.S. degree stand for something and always will. But if a technician can perform many jobs that traditionally belong to the engineer, they both stand to gain. The technician, because he gets much of the engineer’s salary, satisfaction and recognition; the engineer, because he is free to do work which only a man with his formal training can do. When everybody wins, and nobody loses, it’s the sign of a good thing.”
Since Bill Miles joined IBM, opportuni-
Home-town assignment pleased Miles’ wife, son, twin girls
ties in the Project Sage program, destined for long-range national. importance, have grown more promising j-han ever. If IBM considers your experience equivalent to an E.E., M.E. or Physics: degree, you'll re- ceive 8 months’ training, valued at $10,000 per man, as a Computer Systems Engineer. If you have 2 years’ technical schooling or the equivalent experience, you'll receive 6 months’ training, as a Computer Units Field Engineer, with opportunity to assume full engineering responsibility. Assignment in area of your choice. Every channel of advancement in entire company open— and IBM is leader in a field that’s sky- rocketing in growth. All the customary benefits and more. WRITE to Nelson O. Heyer, IBM, Kingston, New York. Include the questions you would want answered. You'll receive a prompt reply.
CUSTOMER ENGINEERS: opportunities are also available, locally, for servicing IBM machines, after training with pay. Contact the nearest IBM office.
MILITARY PRODUCTS
DATA PROCESSINGs ELECTRIC TYPEWRITERS TIME EQUIPMENT « MILITARY PRODUCTS
27
26
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RADIO & TELEVISION NEWS
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OU CAN plod along for years, getting a paltry increase now and then, enjoying little security, finding your work dull and drab.
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Today there are over 97,000 radio- equipped police cars; at least 87,000 taxis are radio equipped; 37,730 civil- ian planes have radio; 35,000 Ameri- can ships have ‘radio.
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Since its founding in 1927, CREI has provided thousands of profes- sional radio men with technical educations. During World War II CREI trained thousands for the Armed Services. Leading firms choose CREI courses for group training in electronics, at company expense, among them United Air
January, 1957
CAPITOL RADIO ENGINEERING INSTITUTE
ECPD Accredited Technical Institute Curricula DEPT. 11D, 3224 léth St., N. W., Washington 10, D. C.
Please send me your course outline and FREE IIlustrated Book-
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IN WHAT BRANCH OF ELECTRONICS ARE YOU MOST INTERESTED?
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JAY CARVER has been appointed to the post of advertising and sales promotion manager of Elec-
tro-Voice, Inc., Bu-
chanan, Michigan ©
manufacturer of mi-
crophones and high-
fidelity equipment.
Mr. Carver moves up to his new posi- tion after six months of managing wood product sales of the firm. He was for- merly advertising manager of Cabin- art, a division of G € H Wood Prod- ucts of Brooklyn, N. Y.
x * * LEON PODOLSKY, technical assistant to the president of Sprague Electric Com- pany, is this year’s recipient of the engineering award presented annually at the Fall Meeting of the RETMA and IRE.
The award, a gold plaque, has been presented each year since 1941 to an individual in recognition of outstand- ing contributions or services to the electronics industry.
Mr. Podolsky’s citation reads: “Awarded for his outstanding contri- butions to international standardiza- tion in the field of components for electronic devices.” He has served as technical advisor and chief delegate of the U.S. on electronic components at the meetings of the International Electrotechnical Commission since 1952. He is also chairman of the RETMA International Standards Committee and chairman of the ASA committee on electronic components.
* * *
MILTON R. SCHULTE who has been a vice-president of Tung-Sol Electric Inc. since 1951 and a di-
rector since 1953
has been elected to
the newly created
post of executive
vice-president.
He joined the firm in 1923 immediately following his grad- uation from Stevens Institute. He has worked for no other firm. Starting as a draftsman, Mr. Schulte became foreman of the lamp department in 1925 and three years later was made superintendent of radio tube manufacture.
ok oa a FEDERAL TELEPHONE AND RADIO COM- PANY has established a Puerto Rican manufacturing subsidiary which will be known as FEDERAL CARIBE, INC. The new unit is located at Santa Isabela, near Ponce, on the southern shore of the island. It will produce selenium rectifiers, starter switches, and other
SLRUVEiTLEY
RADIO & TELEVISION NEWS
ires LT Sout ces—sus 65 35 5
electronic components ... VARIETY ELECTRIC CO., INC. of Newark, N. J. has changed its corporate name to VARIETY ELECTRONICS CORP. to more accurately reflect the category of prod- ucts distributed by the firm... L. A. YOUNG SPRING & WIRE CORPORATION has purchased the assets of GONSET COMPANY, INC., Burbank, Cal, manu- facturer of communications electronic equipment. It will be operated as a division of the parent firm . . . MAGNE- CORD, INC. of Chicago has established a MAGNE MATIC division to specialize in the development and manufacture of magnetic tape recording equipment for industrial applications.
* x * DR. BEN R. GOSSICK has been appointed to the post of chief engineer in charge of the circuitry de- partment of the Semiconductor Products Division of Motorola Inc.
In his new posi- tion, he will be re- sponsible for tran- sistor electrical evaluation, testing procedures, and specifications. His func- tion also includes customer circuit en- gineering and transistor circuitry re- search.
He was formerly associated with the Oak Ridge National Laboratory and RCA. He will make his headquarters at the division’s Phoenix, Arizona plant.
ok * * SYLVANIA ELECTRIC PRODUCTS INC. has opened an 87,000 square foot distri- bution center in Los Angeles and an- other 79,000 square foot unit in the San Francisco area, more than doub- ling its warehousing and sales office facilities in California . . . FAIRCHILD RECORDING EQUIPMENT CO. has moved to a new and larger plant at 10-40 45th Avenue, Long Island City 1, N. Y.... CANNON ELECTRIC COMPANY of Los Angeles has added 100,000 square feet of space to its East Coast facility with the signing of a 10-year lease in the Salem, Mass., Industrial Center. It will be used for manufacturing purposes . . » The Radio Division of BENDIX AVIATION CORPORATION has opened a new 100,000 square foot Engineering Center which will be used for projects covering guided missiles, ground and airborne radar, aviation communica- tions, and mobile two-way radio sys- tems . . . ELECTRONIC ENGINEERING COMPANY OF CALIFORNIA has broken ground for a new laboratory and gen- eral office at 1601 E. Chestnut Street in Santa Ana. The 41,000 square foot building is expected to be completed by the end of March ... The Elec-
RADIO & TELEVISION NEWS
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January, 1957
an
tronics Division of FAIRCHILD CAMERA AND INSTRUMENT CORPORATION has moved into its new headquarters on
Aerial Way North in the Landia In- |
dustrial Park, Syosset, Long Island, N. Y. ... REEVES INSTRUMENT COR- PORATION has established a West Coast office at 1216 Fifth Street, Santa Mon-
ica, Cal. This office will handle the |
Los Angeles area ... FEDERAL ELEC- TRIC CORPORATION has opened a new
plant on Garibaldi Ave. in Lodi, N. J. |
The new building will house the Train- ing and Publications Divisions of the company . . . ELECTRONICS MEASURE- MENTS CORPORATION has moved its entire manufacturing and executive facilities to 625 Broadway in New York . . . UNITED STATES DYNAMICS COR- PORATION has dedicated building and production facilities at 1250 Columbus Avenue in Boston, Mass. The new 20,000 square foot plant will be used for the manufacture of electronic com- ponents and systems and for research and development of commercial and military gear ... The offices of the TV receiver department of HOTPOINT CoO. have been moved to 715 S. 25th Ave., Bellwood, Ill. . . . GENERAL PRE- CISION LABORATORY INCORPORATED has started construction on its second engineering building in Pleasantville, N. Y. The 22,000 square foot building is expected to be ready for occupancy by the end of July . . . WHEELER LABO- RATORIES, INC. has begun construction of a second laboratory to be devoted to antenna engineering in Smithtown, N. Y. The plant will be an 11,000 square foot unit, forming one terminal of a 1000 foot antenna range . . . WARWICK MANUFACTURING CORPORATION of Chicago has opened a new research center in Zion, Illinois . . . Ground has been broken on Pleasant Valley Boule- vard in Altoona, Pa. for a 190,000 square foot, fully air-conditioned tube plant by SYLVANIA ELECTRIC PROD- UCTS INC. Completion is scheduled for late 1957... U.S. ENGINEERING CO., INC. has moved to 5873 Rodeo Road, Los Angeles 16, Cal. ... ELECTRO- MEASUREMENTS, INC. has moved into a modern 26,000 square foot plant at 7524 S.W. Macadam Ave., Portland 1, Ore. * > ak
VINTON K. ULRICH has been named head of applications engineering for Raytheon Manufacturing Company’s Receiving Tube Division. He was for- merly general sales manager of David Bogen Co., Inc... . DR. GEORGE ROKA has joined Marvelco Electroniés Di- vision as director of the semiconductor division. He was formerly manager of semiconductor activities at Delco .
The broadcast and television equip- ment department of Radio Corporation of America has appointed EDWIN C. TRACY to the post of manager. He will make his headquarters in Camden, N. J... . ROBERT L. SHAW has been named national sales manager of the radio and television division of Syl- vania Electric Products, Inc. The post is a new one .. . Standard Coil Prod-
(Continued on page 168)
Free!
An FCC license can be your Guarantee of Success in Electronics!
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Here’s proof FCC Licenses are often secured in a few hours of study with our coaching at home in spare time...
Every month our trainees get jobs like these:
Boyd Daugherty: Irving Laing:
“I am pleased to inform you “Your lessons are helping me a
that I recently secured a posi- tion as Test Engineer with Mel- par, Inc. (Subsidiary of Westing- house). A substantial otey in- our ond ate go was involved. My c ne CS a land Institute training play . : : : : Fert eign, ~~ Fadio and T. V. engineer at W1 VS and WDTR a major role in qualifying me for this position. in Detroit, Michigan.” Boyd Daugherty I L. Laing 105 Goodwin Ct., Apt. C 15887 Robson _ Falls Church, Va. Detroit 27, Michigan
Top Grade Employers Like These
AMERICAN AIRLINES: “We are very interested in receiv- ing applications from Cleveland Institute graduates.”
BENDIX RADIO: “We shall look forward to receiving com- pleted applications from your students.”
PHILCO: “We have employed a great number of well qual- ified electronics personnel who were graduates of Cleveland Institute.”
WESTINGHOUSE: “We would appreciate your listing our current openings in your monthly Job Opportunities.” RADIO & TELEVISION NEWS
Lo
Aeroje Ameri Ameri
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Branif Burrou Capit Contin Conva Gener Glenn Good IBM
Janua
WE GUARANTEE
TO TRAIN YOU UNTIL YOU RECEIVE
YOUR FCC LICENSE
If you fail to pass your Commercial License exam after completing our course, we guarantee to continue your training, without additional cost of any kind, until you successfully obtain your Commercial license.
- Name and Address License Walter Eggers, Pacific Grove’ Ist Paul Reichert, West Salem, Ohio 2nd Harold Phipps, LaPorte, Indiana Ist John H. Johnson, Boise City, Okla. 2nd James Faint, Johnstown, Pa. Ist
+ Bob Thompson: ,
In a year and a half, he received his first class FCC license. He isn’t through yet. He is continuing his training with Cleveland Institute. His 1 is much higher than his mt position with Eastern Air- lines, so, he is adding technical “know-how’’ to his practical experience. You can be sure he will go far.
Bob Thompson
2935 aenued Drive
Nashville 14, Tennessee
James Glen:
When Jim enrolled, he was a temporary employee of the City of Tacoma, “Washington. He was mg ing wire and install an interoffice phone system the space of 14 months, he completed the Master Course and received his first class | license. He is now installing and maintaining mobile and microwave equipment.
James S. Glen, Jr.
2920 Knob Hill Road
Tacoma, Washington
Accredited by Nationc! Home Study Council
Cleveland Institute of Radio Electronics Desk RN-1 ; 4900 Euclid Ave., Cleveland 3, O.
; i fh Please send Free Booklets prepared to help me Look To Cc LEVE N D get ahead in Electronics. | have had training or — H Al STITUTE experience in Electfonics as indicated below:
[] Militory. - [[] Broadcasting Aerojet-General International Telephone & Tele Oo Radio-TV Servicing [1] Home Experimenting
American Airlines graph Co. ’ : American Telephone & Tele- Mohawk Airlines (J Manufacturing [_] Telephone Company graph Co. Motorola (J Amateur Radio ([) Other.
- Bendix Radio North American Aviation, Inc. 2 Braniff Airways Northwest Airlines In what kind. of work are you In what branch of Electronics Burroughs Corp. Philco now engaged?_________._ |_ are you interested?
Capital Airlines RCA
Continental Air Lines, Inc. Ryan Aeronautical Co.
Convair TWA
General Electric Union Switch & Signal Co,
Glenn L. Martin Co. United Airlines
Goodyear Atomic Corp. Western Electric Co. i Zone State
IBM Westinghouse Electric Co. Special Tuition Rates to Members of Armed Forces *(Plus Many Others)
January, 1957
A NEW
FRONTIER
FOR
TECHNIGIANS
RCA offers an opportunity for you to apply your technical skill to its Missile Test Project at Patrick Air Force Base, Florida— “Launching Site of the Satellite.”
Here at the world’s longest missile testing range, extending from Florida far across the South Atlan- tic, you can enjoy improved status with the recognized leader in Elec- tronics. Unprecedented growth op- portunities are offered in various phases of data acquisition, transmis- sion and processing, including Radar —Communications—Optics— Computers— Timing— Telemetry.
At RCA’s Missile Test Project you will enjoy technical advancement
34
combined with famous Florida liv- ing. Your family will appreciate the ideal climate—allowing year ‘round outdoor activities—and pleasant social surroundings.
Immediate assignments are avail- able in Florida, the Bahama Islands, and aboard tracking ships in the South Atlantic. Attractive home leave policy and salary dif- ferential make the Bahama Islands and tracking ship assignments especially attractive for single men.
Let the Missile Test Project be- come your symbol of the future. Join in our assault on the frontier of space!
For complete information about this new and challenging field, write to:
Personnel Manager, Dept. N-16A RCA Service Company, inc. Missile Test Project
P.O. Box 1226
Melbourne, Florida
RADIO CORPORATION of AMERICA
RADIO & TELEVISION NEWS
ae ere
WEW! coror and Black-&-White LAB & TV 5” OSCILLOSCOPE #460 KIT $79.95. Wired $129.50
The FINEST professional 5 mc wide-band scope value. Ideal for research, h-f & complex waves, plus Color & Monochrome TY servicing. Flat from DC to 3.58 mc +1 db (color burst freq.), flat DC to 4.5 mc +1, —3 db. Vert. sens. 25 rms mv/in. Vert. Z 3‘megs. Has the following outstanding fea- tures not found in scopes up to several times its price, kit or wired: VERTICAL AMPLIFIER: direct-coupled (DC) thruout to eliminate |-f phase shift; push-pull thruout for negligible distortion; K-follower coup- ling between push-pull pentode stages for extended h-f resp. (minimizes h-f phase shift, extends use- ful resp. to 10 mc); full-screen undistorted vert. defl; 4-step freq-compensated decade step attenu- ator up to 1000:). SWEEP CIRCUIT: perfectly linear sweeps, 10 cps — 100 ke (ext. cap. for down to 1 cps); pre-set TV vert. & hor. positions (30 & 7875 cps); automatic sync. ampl. & limiter elim- inates sync amplitude adj. PLUS: direct or cap. coupling; bal. or unbal. inputs; edge-lit engraved lucite graph screen; dimmer; anti-glare filter; bezel fits std photo equipt. OTHER IMPORTANT FEATURES: High intensity: trace CRT. Finest sq. wave resp. (.06 usec rise time). Push-pull hor. ampl., flat to 400 ke, sens. 0.6 rms mv/in. Built-in voltage calibration. Intensity mod. Sawtooth & 60 cps outputs. Astigmatism control. Retrace blank- ing. Instant, drift-free full-screen vert. positioning & 2X full-screen hor. positioning. Bal., eal., astig. adj. externally accessible. 5UP1 CRT, 2—6AU8, 2-6CB6, 1-12AU7A, 2-6J6, 1-6AX5, 1-1V2. Deep-etched satin aluminum panel, rugged grey wrinkle steel cabinet. Designed for easy building at home with no special equipment. 13” x 844” x 16”. 30 Ibs. SCOPE DIRECT PROBE* +PD: KIT $2.75. Wired $3.95. Eliminates stray- pick-up & signal re-radiation. SCOPE DEMODULATOR PROBE* +PSD: KIT $3.75. Wired $5.75. Demodu- lates AM carriers between 150 kc and 250 mc. SCOPE LOW CAPACITY PROBE* =PLC: KIT $3.75. Wired $5.75. For signal tracing in high frequency, high impedance & wide-band circuits (as in TV) without distortion from overloading or frequency discrimination.
for COLOR and Monochrome TV servicing
-— Mew! PEAK-to-PEAK VIVM #232 & UNI-PROBE (pat. pend.) KIT $29.95. Wired $49.95
UNI-PROBE: exclusive with EICO! Terrific time-saver! Only 1 probe performs all func- tions—a half-turn of probe-tip selects DC or AC-Ohms.
The new leader in professional peak-to-peak VT VMs. Latest circuitry, high sensitivity & precision, wide ranges & versatility. Calibration without removing from cabinet. New balanced bridge circuit. High Z input for negligible loading. 4/2” meter, can’t-burn- out circuit. 7 nen-skip ranges on every function. 4 functions: +DC Volts, —DC Volts, AC Volts, Ohms.
Uniform 3 to | scale ratio for extreme wide-
range accuracy. Zero center. One zero-adj. for all functions & ranges. 1% precision ceramic multi- plier resistors. Measure directly peak-to-peak
voltage of complex & sine waves: 0-4, 14, 42, 140,
420, 1400, 4200. DC/RMS sine volts: O-1.5, 5,
15, 50, 150, 500, 1500 (up to 30,000 v. with HVP probe, & 250 mc with PRF probe). Ohms: 0.2 ohms to 1000 megs. 12AU7, 6AL5, selenium rectifier; xfmr-operated. 82” x 5” x 5”. Deep- etched satin aluminum panel, rugged grey wrinkle steel cabinet. 7 lbs.
DELUXE PEAK-to-PEAK VTVM #249
with 72" METER & UNI-PROBE (pat. pend.) KIT $39.95. Wired $59.95
All the advanced & exclusive features of #232—PLUS the extra convenience and readability of its big 7/2” meter. Your ideal bench instrument.
VTVM RF PROBES* +PRF-11 or PRF-25:
KIT $3.75. Wired $4.95. Accuracy +10%. Use with any
1l or 25 megohm VTVM.
VTVM HV PROBE #HVP-2: Wired $4.95. Complete
with multiplier resistor. Measures up to 30 kv with
any VTVM or 20,000 ohms/volt VOM.
150 ke to 435 mec with ONE generator! New! RF SIGNAL GENERATOR #324 KIT $26.95. Wired $39.95 for COLOR and Monochrome TV servicing
New wide-range, stable generator — better value then genera- tors selling at 2 or 3 times its cost! Ideal for: IF-RF alignment, signal tracing & trouble-shooting of TV, FM & AM sets; mar- ker gen.; 400 cps audio testing; lab. work. 6 fund. ranges: 150-400 ke, 400-1200 ke, 1.2-3.5 me, 3.5-11 me, 11-37 mc, 37-145 me; 1 harmonic band 111-435 me. Freq. accurate to +1.5%; 6:1 vernier tuning & excellent spread at most import- ant alignment freqs. Etched tuning dial, plexiglass windows, edge-lit hairlines. Colpitts RF osc., directly plate-modulated by K-follower for improved mod. Variable depth of int. mod. 0-50% by 400 cps Colpitts osc. Variable gain ext. mod. ampli- fier: only 3.0 volts needed for 30% mod. Turret-mounted coils slug-tuned for max. accuracy. Fime & Coarse (3-step) RF attenuators. RF output 100,000 uv; AF sine wave output to 10 volts. 50-ohm output Z. 5-way jack-top binding posts for AF in/out; coaxial connector & shielded cable for RF out. Tubes: 12AU7, 12AV7, selenium rectifier; xfmr-operated. Deep-etched satin aluminum panel, rugged grey wrinkle steel cabinet. 8” x 10” x 4%”. 10 Ibs.
The specs are the proof...
NEW BEST BUYS
Y TEIGO",
COMPLETE with Preamplifier, Eavalizer and Control Section
New! 20-WATT Ultra-Linear Williamson- type HIGH FIDELITY AMPLIFIER *HF20
KIT $49.95. Wired $79.95 |
A low-cost, complete-facility amplifier of the highest quality that sets a new standard of performance at the price, kit or wired. Every detail, down to the etched, brushed solid brass control plate, is of the fine quality EICO is famous for.
‘Rated power output: 20 watts (34 w peak). IM distortion (60 eps: 6 ke/4:1) at rated power: 1.3%. Mid-band harmonic distortion at rated power: 0.3%. Maximum harmonic distor- tion between 20 and 20,000 eps at 1 db under rated power: approx. 1%. Power response (20w): +0.5 db 20-20,000 cps; +1.5 db 10-40,000 cps. Frequency response (%4w): +0.5 db 13-35,000 cps; +1.5 db 7-50,000 cps.
5 feedback equalizations for LP’s & 78’s including RIAA. Variable turnover feedback tone controls do not affect volume & permit large boosts or cuts at either end of audio spectrum with mid-freqs. unaffected. Loudness control & separate level set control on front panel. Low Z output to tape recorder. 4 hi-level switched inputs: tuner, tv, tape, auxiliary (xtal/cer- amic phono or 2nd tuner); 2 low-level inputs for proper loading with all leading magnetic, FM & quality xtal cart- ridges. Hum bal. control. Extremely fine output transformer has interleaved windings, tight coupling, careful balancing & grain-oriented steel. 842” x 15” x 10”. 24 Ibs.
These amazing EICO values are NOW IN STOCK at your nearest distributor. Examine them side-by-side with ANY competitor. You'll see
for yourself why indeed EICO is your BEST BUY. Fill out coupon on reverse page.
TEILCTG
january, 1957
TURN PAGE FOR MORE EICO VALUES...
the specs are the test that tells who’s best!
for COLOR & Misaasliias TV servicing
NEW! DYNAMIC CONDUCTANCE TUBE & TRANSISTOR TESTER #666 KIT $69.95 WIRED $109.95
Unexcelled testing thoroness & accu- racy. Checks transister collector cure rent & Beta using internal dc power supply. Tests all receiving tubes includ- ing subminiatures (& Color & Mono- chrome tv pic tubes with accessory adapter). Composite indication of mu- tual conductance, plate conductance, & peak emission. Simultaneous sel. of any 1 of 4 combinations of $ plate, 3 screen, & 3 ranges of control grid voltage. Grid voltage variable over 3 ranges with 5% accurate pot. New series-string voltages for 600, 450 & 300 ma types. 5 ranges meter sens. with 1% precision shunts & 5% accurate pot. 10 SIX-position lever switches for free-point connection of every tube pin or cap. 10 pushbuttons for rapid insert of any tube element in leakage circuit & speedy sel. of individ- ual tube sections. Direct reading of inter-element leakage in ohms. New gear-driven rollchart. Steel case with cover & handle. Sensitive 200 ua meter.
for COLOR & Monochrome TV servicing
TV-FM SWEEP GENERATOR
& MARKER *368 KIT $69.95 WIRED $119.95
The FINEST service instrument of this type ever offered in either kit or wired form at ANY price! Outstanding ease & accuracy in FM & TV (including Color) alignment. Entirely electronic sweep eireuit with accurately biased Increduc- tor: superb linearity on both sides of selected center freq. Newly-designed AGC circuit automatically adjusts osc. for max. output on each band with min. amplitude variations. Sweep range 3-216 mc in 5 OVERLAPPING FUND. BANDS. Sweep width continu- ously variable from 0-3 mc lowest max. deviation to 0-30 mc highest max. deviation. Variable marker gen. range from 2-75 mc in 3 FUND BANDS plus a calibrated harmonic band (60-225 mc). Variable marker calibrated with int. xtal marker gen. 4.5 mc xtal included, Ext: marker provision. Double pi line filter. Edge-lit hairlines eliminate parallax.
TUBE. TESTER #625 KIT $34.95 Wired $49.95 * tests 600 Tl
in tubes «illuminated rolj-chart
Pix Tube Test Adapter .......... $4.50
FREE 1957 EICO CATALOG!
Tells you how to SAVE 50% on your test equipment costs!
New! GEIGER COUNTER 7803 KIT $19.95 Wired $29.95
Professional, all-electronic, sensitive, rugged—at fowest cost! indicates by) neon lamp & headphone clicks.
# KIT $79.95 Wired $128.50
VACUUM TUBE VOLTMETER 221 KIT $25.95 Wired $39.95 DELUXE VTVM 214 (7¥2" METER) KIT $34.95 Wired $54.95
RF SIGNAL GENERATOR #320 KIT $19.95 Wired $29.95 150 kc-34 mc, calibrated har- monics to 102 mc. Pure or mod. RF, & Colpitts osc. 400 cps sine outputs. |
KIT $12.95 Wired $15.95 Muiti-range ac/de voltmeter, amme- ter, ohmmeter, wattmeter, leak- age checker for , home & outo re-
pairs.
$944 FLYBACK
TRANSFORMER & YOKE TESTER KIT $23.95 Wired $34.95 © fast check all
flybacks in or out of set.
Range 500 kc-- 228 mc on fund. Cont. sweep width —
0-30 m
KIT $34.95 Wired $49.95
TV/FM SWEEP GENERATOR #360
1% accuracy on all 7 ranges. "hon 150 mc. Volt reg.
KIT $39.95
DELUXE RF SIGNAL GENERATOR £315
6V & 12V BATTERY ELIMINATOR & CHARGER #1050
KIT $24.95 Wired $39.95
DELUXE MULTI-SIGNAL TRACER 3147°
RC BRIDGE & RCL COMPARATOR $9508
ng
So
HI-Fl PREAMPLIFIER #HF-61
KIT $24.95 sid $37.95. With Pow- er Supply: KIT $29.95. Wired $44.95
Feedback circuitry thruout! Preamp-| liter, tone controls, — &
Ohms/Volt MULTIMETER #565
KIT $24.95 Wired $29.95
1000 Ohms/Voit MULTIMETER # 536
KIT $12.90
Wired $14.90
VTVM PROBES KIT a ana parses! as poe
High Voltage Probe-1 , High Voltage Probé-2 .
— gen. ble fil K-follower outp For FREE 1957 cotolog, moil coupon NOW! | 8ICO, 84 Withers Street io g Brooklyn 11, New yoo eg
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Prices 5% higher on West coast
Over a Decade of Know-How & Value Leadership in Kits & Instruments
84 Withers St. ¢ Brooklyn 11, N.
and subject to change without notice.
i
g Home Address.
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Over 1 Million Sold to Date!
RADIO & TELEVISION NEWS
Behind t
1946, officials of the Federal gov-
ernment and the University of Pennsylvania, several luminaries of the world of science, and representa- tives of the press met at the Moore School of Electrical Engineering, on the University of Pennsylvania campus in Philadelphia.
Norbert Wiener, the MIT math pro- fessor who was to start a whole cross- section of America using the term cybernetics, arrived characteristically without an overcoat. Others parked their wraps and were shown into a large room at the back of the build- ing. Racks of electronic apparatus surrounded them. They were told they were inside an electronic calculator which could solve complex differential equations—such as an equation in ex- ternal ballistics—faster than most peo- ple could state the problem. Some were excited, others politely interest- ed, a few were bored. They watched the electronic gadgetry being put through its paces: punched cards with problem data were fed in, cards with answers were punched seconds later. Someone checked the results; they were correct. The press asked some questions, got some answers, and then everybody went to dinner.
These men had been summoned to witness the first public showing of the Moore School’s electronic numerical integrator and calculator (a mouthful of description shortened by Army Ordnance officers into the acronym ENIAC). It was not an occasion that seemed particularly world-shaking, but the outgrowths from this machine have been giving the world its share of shudders ever since.
The whole pattern of our existence is being shaped by electronic comput- ers, or “giant brains,” to use Edmund C. Berkeley’s much abused term. These
0: A RAW afternoon in February,
January, 1957
e Giant Brains
The IBM 650 magnetic drum data processing machine built tor commercial use. This machine is designed to meet the ac- counting and computing needs in areas between those now served by the company’s very large and its smaller machines,
Part 1. Historical development and principles of electronic
computers. Here's the story about the devices that are now
beginning to shape our lives. To be concluded next month.
computers can not only solve complex problems in advanced mathematics, but models now in existence can han- dle all kinds of information, from a payroll to the Bible. One, the Rem- ington Rand “Univac,” a lineal de- scendant of the ENIAC, was recently used by the Thomas J. Nelson Pub- lishing Company to compile the Con- cordance for the Revised Standard Version of the Holy Bible. Other sys- tems are gradually infiltrating our daily lives: our social security ac- counts, our insurance policy informa- tion, our income tax records, all are being converted onto files of magnetic tapes, which can be swiftly and effi- ciently processed by these automatic electronic computers.
The Monster on the Second Floor
The reactions of people associated with them are as varied as opinions about the proper proportions for a martini. Some people—notably the de- signers—feel that these computers are the greatest boon to mankind since the invention of the round wheel. Others, seeing phantoms of technologi- cal displacement, redeployment, and unemployment, regard the introduc- tion of electronic brains into everyday affairs with great distaste. More con- sidered opinions place atomic energy and automatic computers on the same level, as the two most important tech- nological advances to have come out of the War.
In the New York office of one of the major manufacturers of the giant elec-
tronic computers, a system has been set up to operate as a computing serv- ice bureau on the second floor of the building. One of the old-line employees of this corporation refers consistently to the machine as “the monster on the second floor.’”’ No amount of persua- sion, exhortation, or scientific evi- dence can convince him that it is any- thing but a monster.
War Babies
ENIAC, the first of all these elec- tronic ‘“monsters”—no more monster than the thermostat that turns your heat on and off—has been working around the clock at Aberdeen Proving Grounds ever since it was moved there in 1948. Another of the computer in- dustry’s grandparents sits where it was first built, at Harvard. This is the famous Aiken Relay Calculator Mark I, first of all truly automatic com- puters, built in 1944 by Harvard Com- putation Laboratories for the U. S. Navy. The two of them, different in concept but complementary to each other, have sired many progeny.
Mark I was not electronic; ENIAC was. Mark I was automatically se- quenced, which is to say, it was capa- ble of automatically performing a se- ries of instructions fed to it from punched paper tape; ENIAC recog- nized patterns of instructions set up in advance on wiring panels. Modern computers, which are generally both electronic and automatically sequenced, are logically descended from both “old” designs.
37
et “ALY iE eR 8m ; ee t
All computing and processing of information in the Harvard Mark I was performed by means of high- speed relays. This is what the calculator looks like today, after some modifications have been made.
Mark I and ENIAC were both “war babies.” Army Ordnance, trying to supply complete ballistic data on new weapons to Army field commanders, had pricked up its ears when John W. Mauchly, then an assistant professor on the staff of the Moore School, and now an executive of Remington Rand’s “Univac” division, had suggested an electronic calculator as a possible so- lution; Ordnance funds sponsored the construction of ENIAC. Mark I, de- signed by Harvard’s Howard Aiken and built by his staff in cooperation with International Business Machines Corporation, was fostered by the simi- lar needs of Navy Ordnance.
From these original wartime projects have sprung the burgeoning family of electronic digital computers—comput- ers which recognize and electronically process actual numbers, or alphabetic characters, and not varying voltage levels, or turns of a cogwheel or gear or axle. The latter, called analogue computers, form a completely different family, with a somewhat similar her- itage, but with different parents, and different uses.
The Tributary Currents
Several separate streams have joined to form the torrent of activity that the computer industry has become.
The principal headwater is an old and familiar one: man has always sought ways of harnessing nature to serve him. Mathematicians are no ex- ception, and creative mathematicians especially have frequently bridled at the plain stickwork involved in the rigorous proofs of their theories. Pas- cal, Leibnitz, Gauss, and Maxwell are among the great scientists who de- signed and built mechanical aids to calculation. These machines were of some help to their creators, but of little general use.
Another stream first was struck by
38
a watchmaker named Jacques de Vau- canson, who, in 1741, invented a deli- cate automatic loom for weaving fig- ured silks. The designs in the silks were established by patterns of holes punched in a metal drum; the holes controlled the raising and lowering of the treadles. In 1804, Joseph Marie Jacquard adapted the idea to a much larger scale for weaving tapestries, rugs, and other heavier materials. To increase the utility of his automatic loom, Jacquard used as_ controls punched sheets of stiff paper which could be changed fairly easily. Within eight years, eleven thousand Jacquard looms had been placed in operation in France.
The name of Charles Babbage, one of the two men in history ever to hold the Lucasian professorship of mathe- matics at Oxford University, is a re- vered one in the computer field, for Babbage was the first to envisage a truly general-purpose computer. He also merged the de Vaucanson-Jac- quard idea, of storing information as punched holes in a sheet of paper, with the idea of mechanical computa- tion.
Babbage began work on what he called a difference engine in 1823. The purpose of the engine was to provide mechanical assistance for advanced mathematical computations. The Brit- ish government offered some financial support to his project, and he was able to draw up working diagrams and specifications. But this was the era of Watt’s steam engine, when the cri- terion for the fit of a piston within the cylinder wall was that a thin sixpence could just be slipped between the two; built to such tolerances, Babbage’s difference engine, and his later ana- lytical engine, could never be made to produce reliable answers. Eventually the government withdrew support, and the Babbage designs became historical
curiosities. Many of today’s mechani- cal and electronic calculators, however, possess a logical organization remark- ably similar to the analytical engine which was the triumph and despair of Babbage’s life.
Enter the Census Bureau
Mechanical tabulators, capable of simultaneously registering horizontal and vertical sums,“ were the next im- portant development. These grew, quite naturally, out of the needs for statistical analysis, and many of the most important advances were made in the U. S. Bureau of the Census. For example, Charles Seaton, who was Chief Clerk of the Census Bureau, in- vented such a mechanical tabulator in 1872. And in 1887, Dr. Herman Hol- lerith, then chief of Census’ tabulation section, further adapted the Jacquard punched-paper control system to the accumulation of statistical data. This was a most important stride in me- chanical computation, for it introduced into a working system the concept of mechanically stored (remembered) in- formation, which could be used for many calculations or tabulations with- out the necessity for re-entering the data from a keyboard. The Hollerith equipment was one of the ancestors of familiar punched-card equipment.
During the eleventh decennial cen- sus (1890), another member of the Census Bureau staff, James Powers, developed another kind of mechanical tabulator which also used punched cards. The Hollerith holes were rec- tangular; the Powers holes were round. Both types of equipment were used by Census for years—are still in use, in fact. Both men left the Census Bureau to merchandise their ideas in the commercial world. Descended from the Powers’ idea are the familiar Rem- ington Rand and Underwood-Samas round-hole cards, while Hollerith’s idea
RADIO & TELEVISION NEWS
is fou tional des Jus inven “aritl today ented. these Willia the fi in qui ances’ lator, high-s comp the at For the vz ulator the ti chines chanic third tually cembe an el could electr first » autho: cles 4 Jorda! modifi trigge which televis blocks puter Whi growil small the co device succin keepin forma‘ capaci center and e> ties, m began ics to more f
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is found in the equipment of Interna- tional Business Machines, Compagnie des Machines Bull, and others.
Just prior to Hollerith’s and Powers’ inventions, a host of mechanical “arithmetic engines,’’ which we would today call adding machines, were pat- ented. One of the most important of these was the 1885 adding machine of William Seward Burroughs, probably the first to be designed for production in quantity. These machines were the ancestors of the modern desk calcu- lator, now emerging, complete with high-speed electronic and magnetic components, as a serious contender for the attention of the computing public.
For years following the invention of the various kinds of punched-card tab- ulators and calculators—until about the time of World War II—these ma- chines were the highest order of me- chanical aids to computation. But the third major contributory stream ac- tually had appeared as early as De- cember, 1919, when a paper describing an electronic “trigger circuit” that could be used for counting pulses of electrical energy was published in the first volume of Radio Review. The authors of the paper were W. H. Ec- cles and F. W. Jordan; the Eccles- Jordan trigger circuit, and its many modifications—multivibrators, one-shot trigger pairs, and so forth—all of which are familiar to the world of television and radar, are foundation blocks of the electronic digital com- puter as we know it.
While punched-card calculators were growing larger and more complex, a small group of scientific minds saw the coming of an era when mechanical devices, however fast, efficient, and succinct, would not be capable of keeping pace with the need for in- formation. All over the country, the capacity of punched-card calculator centers was exceeded and expanded and exceeded again. In the late thir- ties, men in widely separated activities began asking “can we apply electron- ics to this problem?” And more and more frequently, the answer was “yes.”
The Analogue Computers
A group of scientists and engineers, sparked by the physicist Vannevar Bush, had meanwhile been pursuing another tack. During the twenties, Bush had merged an idea of Lord Kel- vin’s, some of Babbage’s concepts, and the then-recent development of me- chanical torque amplifiers. From this merger, he developed a reliable me- chanical device for the rapid and auto- matic analysis of differential equations. Several of these differential analyzers were built from his plans at various universities in this country and Eu- rope. They were not digital calculators as envisaged by Babbage and as built by the various punched-card manufac- turers. They formed a major group within the completely different class of analogue computers.
Analogue computers derive their name from the fact that they compute by mechanical or electrical analogy.
January, 1957
The turning of a gear, or a set of gears, through part or all of a revolu- tion may be used to represent, by anal- ogy, a parameter in an equation. Or the movement of a diagonal slide in a rectangular frame may represent an- other parameter. Various torque con- verters or torque amplifiers perform operations analogous to mathematical computations.
A simple analogue computer could be made from two circular gears in the ratio of 3.1416 to 1. Turning the larger gear would cause the smaller to be displaced 3.1416 times as much. If angular displacements were shown on a pair of calibrated dials, one could multiply by pi (approximately) on this simple device. Numerical values for a diameter could be entered on the larger dial, and instantaneous approxi- mate values for the circumference would be read onthe dial for the smaller gear. (Such a device would, of necessity, produce approximations, since pi cannot be exactly represented by a ratio of integers.)
Similarly, a large variable resistor might be wound on a card shaped like a sine curve, instead of being wound on the usual rectangular card. The angle of displacement of the wiper arm would then be a parameter in the equation; the voltage applied across the resistor would be multiplied by the sine of this angle when tapped by the wiper. Another wiper 90° dis- placed from the first would simulta- neously produce a voltage analogous to the cosine of the same angle.
Complexes of such mechanical and electrical analogies could be assembled into computing systems which repre- sented the equations of external bal- listics, for example. Such analogue computers were much used during the second World War for artillery fire- control, in conjunction with radar tracking systems. Bell Laboratories, Sperry, Westinghouse, and General Electric, among others, all built ana- logue computers for the Army and
Punched paper tape, such as that which is shown in the photo in use in the famous Bell Relay Calculator, was the source of Har- vard Mark I's instructions and programming.
Navy. More recently, such systems have been used in industry for a.c. network analysis, for the analysis and synthesis of gas distribution systems, and in many instances for the simula- tion of fairly complex machinery or systems (such as missile systems or ultra-thin high-speed propeller blades) prior to their design and construction. Because they work so readily with physical measuring and instrumenta- tion apparatus, and with mechanical or electronic controls, they are also natural choices for the needs of indus- trial automation.
The Differences
Analogue computers are eminently suited for representing involved equa- tions in physical form. In design work, they permit the varying of parameters by analogy, to determine the effect of such variations on the system as a whole. As control systems for indus-
The ENIAC as it looked when it was installed at the Moore School of the University of Pennsylvania. The hundreds of cables, carrying control and
information signals from one part of the <
ther, all had to
P to
be set up before a problem was run. Newer computers are somewhat more sophisticated, can wary operations through a stored program of instructions.
>
The first die-set punch, developed by => Powers for the census of 1910. The op- erator set up on the keyboard all the values to be punched; she then used the knee-treadle to gang-punch the card.
trial automation, they can adjust valves, speed up or slow down transfer systems, and so forth, as required by the standards of the output product desired.
Analogue computers possess two in- herent limitations. First, they cannot easily be used for dissimilar problems. The computer itself is a mechanical or electrical analogy to an _ equation; changing the equation means changing the hardware of the computer. Sec- ond, they are generally only precise to two or three significant figures, de- pending on the fineness of construction; and their accuracy depends, not only on the accuracy of the input data, but also on the instruments which present the answers (calibrated oscilloscopes, meters, counters, etc.), and on the subjective “feel” of the operator who inspects these presentations.
A digital computer can process ordi- nary numbers or alphabetic characters without any trouble at all. It can han- dle continuously variable data only by “digitalizing’” it—sampling the value
40
“= Herman Hollerith’s electric counting ma- chine as used in the 1890 census. The ac- cumulated and tabu- lated results were pre- sented on the counter dials, and had to be copied off by hand.
“= The accumulator of Charles Babbage’s difference engine, from an old woodcut.
of the continuous function at regular time intervals and giving it a numeri- cal representation—and then applying the methods of numerical analysis; but it can generally do far more types of work than an analogue computer, and, once the information is trans- lated into discrete digital form, it never loses a decimal point of pre- cision. Furthermore, the accuracy of the digital computer’s work can easily be checked by inverse operations (proving addition by subtraction, etc.), by identical parallel operations com- pared for identical answers, or by many other means
General-purpose digital computing systems are far simpler than analogue networks (although some of them are much larger); they can basically only add, compare, and discriminate be- tween relative magnitudes, store (or remember, if you prefer) information, and shift the information around. Mostly they subtract by inverse addi- tion, multiply by repeated addition, and divide by alternately performing repeated additions and subtractions. Depending on their discriminatory abil- ities, they can select paths of action, or sort information, or start (or stop) a process. They can, in other words, be empowered to make decisions.
Note well: be empowered to make decisions. The two most mystifying things, to many people outside the
field, are that these machines seem to make decisions, and seem to remem- ber information. Neither one is at all mysterious.
How Machines Remember
Memory, for example, as a machine function, is quite familiar to everyone. A thermostat remembers two things: you tell it how hot you want it to be by setting the value on a dial (which at the same time sets a control con- tact), and a bimetallic thermometer tells it how hot it actually is. When the thermometer tells it that the tem- perature has fallen below your set- ting, it turns on the heat.
A wall switch remembers that you turned it on, but the little button on a flashlight, which must be locked to re- main on, does not; as soon as you re- lease it, it “forgets” it was on and goes out. An annoying characteristic of certain cathode-ray tube phosphors, for television purposes, is persistence; this is nothing more than the phos- phor’s “remembering” the current which excited it into phosphorescence, and continuing to glow after the cur- rent is gone. The characteristic was used to advantage in a type of com- puter memory.
A magnetic tape or wire, or an acetate or vinyl disc, remembers the information put on it for a long time. Materials which are truly elastic can- not remember; they snap back into their normal state too readily. Brittle materials (such as glass after its elas- ticity has been exceeded) are crude memories only, because they cannot be restored. The most concentrated effort in developing memory systems has been expended on hysteretic ma- terials—materials which exhibit a time-lag between the removal of a stimulus and the restoration of the material to its normal state. Magnetic materials are an ideal example; after the magnetizing current is removed, a certain amount of magnetism remains in the material (for a period of time depending on the material). And much of the most fruitful effort in designing and building computer memories has been devoted to magnetics research.
How Machines Make Decisions
The way the thermostat “decides” to turn on the heat is an excellent illustration of the type of decision- making common in the computing ma- chine. When the actual temperature sensed by the thermometer falls below the setting of the contact, the heat comes on. Now the thermostat setting is an artificially established control point, set by a human operator; the control contact is moved closer to or farther from the contact on the bi- metallic thermometer as the operator decides the temperature should be higher or lower. The ability to reach a decision to turn heat on or off is built into the thermostat, in that elec- trical power connects through the two contacts to start a blower motor or automatic stoker.
A computer, which ean compare
RADIO & TELEVISION NEWS
quantities and discriminate between them, can choose one of several paths of action in terms of the relative mag- nitudes of the two quantities. The ability to select the alternate routes is built into the computer; the criteria for the selection are given to it by the controlling human agency. The giant brain and the simple thermostat both have the same degree of mindless un- awareness of what they are doing.
In making its decisions, the com- puter merely transfers control when one quantity equals another, exceeds another, becomes less than another, or goes through zero. If control is trans- ferred to an instruction which tells it to “add,” it adds; “stop,” it stops; “re- wind tape,” it rewinds tape, and so forth.
A set of values can be given to the computer, and its comparison circuits can check each one of the set, making several “yes-no” choices which lead to a compound conclusion. In making these choices, the computer actually seems to be exhibiting a complex type of judgment, but each single decision remains a “yes” or “no” choice. The computer’s secret is that it handles the most complicated problem in the world in the simplest and most primitive steps. It is exactly like an expert player of “Twenty Questions,” who can narrow down on a single object out of all the objects in the world by getting twenty “yes-or-no” answers.
It is an error to romanticize, hu- manize, or personify these devices. They are completely unimaginative servants; they can do exactly what they are told, provided a tube doesn’t burn out, and provided also that what they are told is consistent with what
- they can do; but they can do no more. They are controlled by the men who make them, the men who operate them, and the men who program them. They are especially at the mercy of the men who turn them off when the day is through.
Any time a computer seems to show imagination, it is because someone used imagination in designing its pro- gram. If a “giant brain” solves a prob- lem, it is because someone (a) knew exactly how to go about solving that problem, and (b) knew precisely how to instruct the equipment in the pro- cedures for solving that problem. If anyone ever gets one of these com- puters to write a symphony, for exam- ple, it will be because that person knows the laws of melody and har- mony, counterpoint, orchestral place- ment, musica! structure, and scoring, and knows what limits to set, and knows further how to translate all these laws, maxims, and principles into an abecedarian lingo that the simpleminded “‘brain” can follow. Any- one who can do that could write the symphony himself, in less time than it would take to get the computer to do it. The only advantage would be that the computer could turn out an in- finitude of remarkably similar sym- phonies at an extremely rapid rate.
(Concluded next month)
January, 1957
COVER STORY
RADIO « TELEVISION
xCws
The Univac: An Electronic Brain
for Industry
USINESS and industry, hard-pressed for information to aid management, turn to computers for help—and find it!
The giant electronic computers no longer rank as laboratory curiosities or frightening science-fiction robots. Imaginative busi- nessmen, hard-pressed by a shortage of clerical help, have put them quietly to work in the accounting office, the stockroom, and wherever else work can be routinized.
First of the giant brains to be built spe- cifically for business, the Remington Rand "Univac” has been familiar to most Ameri- cans through the role it has played in pre- dicting the outcome of the last three na- tional elections. On last November's elec- tion evening, with less than '/2 per-cent of the votes (300,000) counted, the "Univac” predicted at 7:15 p.m., EST, that the odds were 100 to | in favor of an Eisenhower landslide and that only 87 electoral votes were likely to wind up in the column of can- didate Stevenson. By midnight, "Univac" had virtually pinpointed the final results with a forecast that President Eisenhower's plurality would be 9,269,524, totalling 58 per-cent of the popular vote to Steven- son's 42 per-cent. (The actual plurality, as of the time of this writing, is very close to 9,312,700).
The first political forecast of "Univac™ was made back in 1952. Then, with 3,380,- 000 votes reported, “Univac" also quoted odds of 100 to |, predicting 438 electoral votes for Eisenhower and 93 for Stevenson (final returns: 442 to 89). At that time, only six "Univac" systems had been sold; these six were all the general-purpose busi- ness data-processing systems that had ever been built. Now about a dozen large office-equipment and electronics manufac- turers are engaged in the building of big computers; half a hundred more companies are building major systems components. What was a minor novelty in 1951 has be- come a several-hundred-million-dollar_in- dustry in the remarkably brief ensuing pe- riod of a little over five years’ time.
The "Univac” system shown on the cover of this month's issue is one of the two such systems installed by the Consolidated Edi- son Company of New York to process its customers’ accounts. Over a hundred large- scale computing systems of this type are already working for American business and industry across the land, in various govern- ment agencies, and in a great many mili- tary establishments and equipment, as are described in the article "Behind the Giant Brains,” in this issue.
The distinguishing feature of the "Uni- vac," when it was introduced in 1951, was not its computing speed; its own predeces- sor, the "Binac,"’ could compute almost two times as fast, and many other machines released before or since were faster than the Remington Rand development. “Uni- vac's" forte was in flexibility; it was one of the first big computers to be able to handle numbers and alphabetic characters with equal ease; it was the very first computing system to use high-speed magnetic tape recording to get information into the com- puter and get results out. High-speed tape input and output, of course, permits the rapid handling and processing of informa- tion in volume. Since most problems of business and industry are characterized by masses of alphabetic or numerical informa- tion on which a relatively small amount of computing or processing is done, input-out- put facilities make the difference between a scientific computer and a data processor which is truly applicable to large-scale busi- ness problems.
“Univac" is also unusual in being a self- checking computer. Over a third of the cir- cuitry in the large central computer cabinet is devoted to checking and verifying opera- tions. Every arithmetical process, all trans- fers of information, and even the instruction set-ups, control functions, and so forth, are checked. Inconsistencies, discrepancies, etc., cause the computer to stop and alert the operator to their presence and location. Since the machine cannot introduce an un- detected error, processed results are thor- oughly reliable.
It is difficult to estimate the savings which have accrued to dozens of computer users, because these savings are both direct and indirect. Not only do companies relieve pressure on their overburdened clerical staffs, and eliminate the many machines which formerly did the work now done by computers; but they also do work which they had never planned, hoped, or intended to do before; work which only a high-speed electronic computer can make possible. And in this realm, of course, there is no basis for comparison. But in every case, companies which have leased or purchased such computers made their decisions to do so after their own staffs had made exhaus- tive surveys which pointed conclusively to substantial and measurable savings over other systems. In this field, as in almost any other, the searching criterion of econ-
omy has brought us into the electronic age. _
Fig. 1. A zip-open holder in the leather carrying case permits exposure of sun battery.
energy the earth receives from the sun is equivalent to approximately horsepower per
|’ HAS long been known that the
one and one-half
square yard. Theoretically, if this en- ergy were harnessed, it could provide an economical and reliable source of universal power. For over two thou-
sand years the world’s scientists have searched for an efficient solar-energy conversion method whereby this free source of power could be put to work.
The search came to an end about two years ago when scientists from the Bell Telephone Laboratories pre- sented to the National Academy of Sciences a “solar battery.” This amazing device could enslave power from the sun by transferring solar en- ergy directly, instantly, and efficiently into electrical energy. The discovery of the solar battery developed out of the study of semiconductors of elec- tricity based on the p-n junction used in transistors. This junction, in this case, is a slice of silicon—the second most abundant element on earth.
First the silicon must be purified until the ratio of non-silicon atoms is 1 to 10,000,000; for although silicon represents 2.5 per-cent of the earth’s crust, pure silicon is rarely found. Then the purified silicon is contami- nated deliberately with a minute amount of impurity. This treatment causes the silicon slice to become n or negative-conductive material. The slice of silicon is treated again by heating it in a tube containing still another impurity. This creates a shallow p or positive layer on the surface.
The result of the process is a p-n junction. When the silicon is now ex- posed to light, the surface becomes positive and the interior negative. With wires connected to the exterior and interior of the silicon, a voltage potential is available for useful work.
42
By PERRY SHENEMAN Admiral Corporation
The solar battery utilizes 6 per-cent of the energy received from the sun. In efficiency, this far exceeds that of thermocouples and photoelectric cells. In fact, it compares favorably with the efficiency of steam and gasoline en- gines. It can be seen readily why re- searchers envisioned that some day solar batteries, possibly containing many silicon cells, would supply cheap, reliable power for home and industrial use.
The Admiral Corporation recognized the solar battery as an excellent po- tential power source for a portable radio, and engineering personnel were assigned the task of determining if such a device were feasible. After 18 months of development work, Admiral Corporation introduced the world’s first sun-powered tubeless radio de- signed for the consumer market.
The solar battery (“Sun Power Pak”) developed to power the radio consists of 32 individual quarter sec- tions of silicon solar cells connected in series. This arrangement delivers a total of 9 volts at 15 milliamperes. The solar cells of the battery are encased in a block of clear plastic with a sili- con oil center. The plastic covering and oil center not only allow the best focusing of sun on the surface of the silicon cells, they also protect the cells from shock damage. The block meas- ures approximately 6 inches long, 4 inches wide, and % inch thick. As shown in Fig. 1, the solar battery is mounted in a common carrying case with its associated receiver during ac- tual use, in such a way that it can be exposed to light while the receiver is in operation.
The solar cells are most efficient when exposed to light of the upper spectral region ranging from red to infrared. They can convert more than 15 per-cent of the sunlight they re-
ceive into electrical power. The unit is so sensitive it can operate satisfac- torily on overcast days, or from an artificial source of light such as an electric bulb or infrared lamp. It can operate over a temperature range of 185 degrees to minus 60 degrees (Fahrenheit). Fig. 2, which shows how the solar battery may be energized by artificial light, also demonstrates the use of the battery on its own stand, separate from but connected to its receiver.
The radio used with the “Sun Pow- er Pak,” automation-produced, con- tains six transistors and two germa- nium diodes. It has a maximum power output of 250 milliwatts and a sensi- tivity of 175 microvolts. Printed wiring is used throughout the chassis.
Without the “Sun Power Pak,” the tubeless radio can be operated by six flashlight batteries. Because the set requires less than one-tenth the power consumed by a conventional portable radio (15 ma.), the batteries will last from 700 to 1000 hours before requir- ing replacement.
Circuit features, shown in Fig. 3, are as follows: A 2N172 n-p-n trans- istor is used as an autodyne convert- er, two 2N146 or one 2N147 and one 2N145 n-p-n transistors are used for the 1st and 2nd i.f. amplifiers. Trans- istors, like triode tubes, must be neu- tralized when used as r.f. amplifiers. Capacitor C, and resistor Re, also Cis and Rw», provide feedback in each stage that is equal and opposite in polarity to the feedback through the relatively high base-to-collector capacity. Since transistor amplifiers have a low input impedance, special tapped if. trans- formers are used. The 1st and 2nd if. transformers are double tuned to pro- vide optimum bandwidth consistent with good selectivity.
The overload diode
RADIO & TELEVISION NEWS
conducts on
Fig. 2. A house lamp will also charge the power pack, shown here on its own stand.
How a practical solar battery, now on the market, energizes a companion transistor radio.
strong signals, and its shunt resistance across the primary of the 1st if. trans- former reduces the gain of the circuit to prevent overloading in a strong sig- nal area. This diode, therefore, acts to “assist” the more conventional a.v.c. action provided by the bias fed to the 1st if. amplifier from the second-de- tector diode, CRz.
The second detector is a standard 1N295 germanium diode. A type 310 p-n-p transistor is used as a first audio amplifier and driver to supply the audio-output amplifier. The output stage uses two 352 p-n-p transistors operated as a push-pull class “B” am- plifier.
The “Sun Power Pak” is sold as an accessory item. When it is plugged into the jack on the back of the radio, the regular battery is disconnected. The radio will then play on electrical energy from the sun or a 150-watt lamp.
The selling price of the “Sun Power Pak” is $185.00. The price seems high until one realizes that pure silicon, from which it is made, presently costs over $300.00 a pound. Eventually, the cost will be reduced as metallurgists develop new refining methods along with mass_ production efficiencies. Nevertheless, the “Sun Power Pak” radio and the unlimited potential
which it represents are important elec- tronic achievements.
Servicing the Radio
In the servicing of transistor radios, precautions must be taken to prevent damage to transistors and other com- ponents designed to operate with rela- tively low supply voltages. Transistors may be damaged by external heat or by heat generated within the circuit as a result of excessive current flow. Most transistors are hermetically sealed. If the seal is broken and the crystal is exposed to air and moisture, the performance of the transistor will be seriously affected.
To prevent possible damage to the transistors while servicing the radio, remember these few basic rules: When replacing components connected to a transistor socket, remove the tran- sistor before doing any soldering. If the transistor should be wired into the circuit without the use of a socket, grasp the lead between the transistor base and the soldered junction with long-nose pliers before doing any soldering or unsoldering. The pliers will help dissipate the heat.
Always solder as quickly as possible. Use only 50/50 or 60/40 (60% tin, 40% lead) low melting-point rosin-core solder. Make certain that the solder- ing iron is hot enough to melt solder quickly before touching it to the sol- dered connection. Also, watch battery polarity closely. Reversing the power- supply battery may damage a trans- istor or one of the low-voltage elec- trolytic capacitors commonly used in transistor radios.
Never remove or replace a transistor without turning the receiver off. In some circuits the resulting voltage transient could do harm. The current
(Continued on page 118)
LO] pT YY onire
CONVERTER
* 2NI47 ® * 2NI46 Fa
IST. IF
2 4
®
~ eit | | |
"
"1 3|
17> 250 MF
UGAT SOURCE che “fi 4h *
| =
s+
SUN POWER > PAK 44
> 1100
C8 yO MME a
Ave BUS
f= 495 KC. L- CHASSIS GROUND
= COMMON GROUND
4 TWO 246 OR OWE 2/47 AND ONE 2W4S WAT BE USED INDIVIDUAL REPLACEMENTS MUST BE EXACT TYPE USED OR SUBSITUTE THE ALTERNATE Pur
Fig. 3. Conventional 6-transistor radio circuit may be operated from 6 flashlight cells (9 volts) instead of the solar battery unit.
2NI85
392
DRIVER OUTPUT
January, 1957
An advocate of high power audio amplifiers for home use gives his reasons—including a simple scope test for you to use to check your own amplifier. Don't miss Hartley's
arguments for lower power
there more controversy than try-
ing to answer the question, “How much power is necessary for high- fidelity reproduction of music in the home?” Opinions range from milli- watts to hundreds of watts, but these opinions are based more on conjecture than on scientific reasoning and ex- periment.
Starting in pre-World War II days many authorities expressed the opinion “10 watts is enough.” They talked about “average” power requirements of a fraction of a watt and “peak re- quirements” ten times average. This concept of ten times peak was based on the sluggish ballistics of vu meters in recording and radio studios and, of course, has no relationship to the dy- namic peaks of musical crescendos. In this post-war period, the dynamic range of records, FM stations, and tape far exceeds that of 78 r.p.m. shel- lac records and AM broadcasts. There- fore, the “ten times” ratio is an ar- chaic concept, and power requirements for modern program sources are far higher than in the days when ten watts were enough.
The author has observed that chang- ing from a 10-watt amplifier to a 25- watt unit made an immediate improve- ment in cleanliness of sound. The 25-watt amplifier handled the loud cli- maxes with obviously improved ease and lower distortion. Changing from 25 watts to 50 watts resulted in fur- ther improvement in sound quality— even on loudspeakers of 25-watt rating and less. Higher power correlated with cleaner, more natural reproduc- tion—particularly in the low-frequen-
44
N there’ in the art of audio is
in his article in this issue. cy portion of the audible spectrum.
These observations are at variance with the opinions of the “ten watts is enough” school; but if we ask “enough for what,” the problem is brought into its true perspective—how much power is required for realistic sound intensi- ties under home listening conditions with home equipment? The qualifica- tion “realistic’’ means that sound pres- sures at the ear are comparable to those in the concert hall, and it also means that distortion is minimized over a wide band and transient attack is preserved. A truly low distortion system does not sound objectionably loud as realistic levels are approached. Systems which are obviously too loud invariably are high distortion systems in which the objectionable qualities stem from irritating distortion content rather than from excessive sound pres- sures.
There have been demonstrations which indicate that a conservatively rated 60-watt system hits overload only occasionally in a concert hall when reproducing the actual sound levels of a small ensemble such as a woodwind quintet. It is unfortunate that these demonstrations did not in- clude the Carabinieri Band, the Bos- ton Symphony, or other groups in which brasses, drums, or massed strings appear. Anyone who has felt the solid impact of the bass drum, or the snarling blare of horns and trum- pets, or the ensemble power of 50 uni- fied string instruments realizes imme- diately that these are loud and take tremendous power to reproduce realis- tically. Yet some superficial tests have been made which indicate that very
little power is required for normal use.
Most tests of power requirements are made by scaling down measured concert hall intensities to living room acoustics and then correcting for speaker efficiency. For example, a measured 200 watt intensity in a con- cert hall might be simulated with one- half watt in the home. To obtain one- half watt out of a 5% efficient speaker requires 10 watts of input; therefore, “ten watts is enough.” This is fine theory which is meariingless because it does not go far enough.
Why High Power?
There are several reasons why sim- ple measurements do not truly show power requirements. First, even if the same actual acoustic power is radiated from a loudspeaker as from the orig- inal sound source, it will not sownd as loud unless stereophonic reproduction is used. Therefore, the same degree of realism requires more power from a loudspeaker than emanates from the actual sound source. Verification of this astonishing fact can be accom- plished readily by paralleling the two channels of a stereo system and noting the drop in the loudness level which occurs even though the total power radiated by the speakers is unchanged. The use of a monaural sound system increases the amount of power re- quired past that which is indicated by direct measurement and computation.
Another little known but highly sig- nificant factor which increases the power required for realistic reproduc- tion is the loss in damping of the loud- speaker which occurs on peak signals. A low internal impedance, approaching a short circuit, is generally the most desirable source for a loudspeaker in order to obtain crisp, solid sound.’ When the amplifier is driven hard, the internal impedance tends to increase, and when overload is reached, there is no longer a short circuiting effect and
RADIO & TELEVISION NEWS
no braking of the speaker cone mo- tion. This results in hangover and blur, and realism is lost.
It is particularly difficult to avoid approaching overload in the low-fre- quency region since the distortion characteristic of combined amplifier and speaker rises at low frequencies. The better the amplifier, the less it contributes to this increased distortion, but the number of amplifiers on the market which deliver rated power at 20 eps at less than 1% distortion can be counted on the fingers of one hand. Even these few will show a rise in dis- tortion at high output levels when they are mismatched by the rising speaker impedance which is found in the low-frequency range. Thus. the overload point (as judged by increas- ing distortion) is reached below the nominal power rating of the amplifier. There are many combinations of am- plifier and speaker where an amplifier rated at 25 watts cannot deliver 2 clean watts to the speaker at 40 cy- cles. Obviously the 25-watt rating fails to indicate the inadequacy of the system to deliver sufficient clean pow- er. Therefore, the nominal rating of a system at mid frequencies must be far in excess of customary expectations in order to be able to deliver power re- quirements at low frequencies.
These considerations indicate the difficulty of trying to theorize concern- ing how much power is required. It weuld seem to be more simple to con- duct an empirical investigation, but even this has difficulties.
An Experimental Approach
The logical way to evaluate power requirements is to set up a system, determine what is an adequate level and measure the power being used. Both of these elements—determination of adequate level and measurement of power used—create problems.
How much level is necessary for realism is a subjective factor which cannot be evaluated by instruments but which requires the considered opinion of people who know how music should sound. In the experiments on which the conclusions of this article are based, a group of people which in- cluded music lovers, audiophiles, and musicians were given a chance to ad- just the loudness level until the play- back from records and tape was at a level which they considered to be real- istic. In addition, tests were made in which a piano was recorded in a living room, and the tape playback was ad- justed so that comparison with the original sound showed equal intensities to a group of knowledgable judges. Thus test levels were those which closely approximated actual instru- mental levels, scaled to living room acoustic environment.
Great difficulties were encountered in setting up an experimental ap- proach to measure the actual power being delivered to the loudspeaker sys- tem. Short duration bursts of sound could not activate meters to furnish accurate readings. The use of neon
January, 1957
lights and similar types of peak meas- uring devices was also found to lead to erroneous conclusions on music with very short duration peaks and of rap- idly changing dynamic characteristics.
The use of an oscilloscope as a volt- meter permitted determination of volt- age output from the amplifier. How- ever, since power is a combination of voltage and impedance (P = E*/Z), and the impedance varies with the frequen- sies used, it was not practical to de- rive power measurements directly by this system. Fortunately, oscilloscope procedures can be used indirectly to establish the power requirements, and this is done as follows:
The signal from the amplifier is con- nected to the vertical input of the scope. The signal to the amplifier is connected to the horizontal input of the scope; and the internal sweep in the scope is shut off. This way the in- put versus the output of the amplifier is shown. Proper adjustment of the gain controls result in an oscilloscope trace such as is shown in Fig. 1A where a straight line with a slope of 45° appears. (This presupposes no phase shift in the amplifier.) As the input to the amplifier is increased, the trace increases in a horizontal direc- tion. As long as the amplifier output is linear and non-distorted, it will in- crease proportionately with the input, and the scope trace will remain linear and at the same slope. As soon as the amplifier approaches overload the vertical extensions of the trace flatten out as shown in Fig. 1B. This type of trace instantly reveals that the amplifier has passed the overload point.
This is a very simple and basic overload test. It does not require knowledge of how much power is be- ing delivered. If an amplifier of a given power rating is overloaded, real- istic reproduction would obviously -re- quire an amplifier of higher power rating. The fact that the overload is a result of inability of the amplifier to deliver its power into a mismatch of impedance—or whatever other fac- tor causes the overload—is immaterial. This type of test proves conclusively whether or not sufficient power capac- ity was available. Further, this test eliminates conditions of speaker over- load and limits the analysis to the power amplifier alone.
The most elegant characteristic of
Fig. 1. is now being slightly overdriven.
(A) Full amplifier output versus input without overload. (C) Here a serious overload occurs and the
this testing procedure is that it also indicates how much more power would have been required in order to have permitted undistorted reproduction. This is established by noting that the horizontal trace is unaffected by out- put clipping. After vertical clipping, the horizontal trace continues to ex- tend if the. input signal continues to increase. Comparison of horizontal trace with the clipped vertical trace can be used to indicate the extent of input signal past the point at which the amplifier is overdriven. This can be used to show how much more power would have been required to handle the input levels used. As an example, in Fig. 1C the horizontal trace is twice that of the clipped vertical trace. This means that the amplifier would have required handling of an input signal twice as large to avoid overload clipping. Since we are talking in terms of linear systems, the output voltage would have been twice as great if clipping had not occurred. Twice as much voltage across a con- stant impedance would have required that the power rating be increased by four times, since power varies as the square of the voltage. In the condition of Fig. 1C the amplifier would have had to have four times the power rating of the one used, in order to have handled the signal without dis- tortion.
Thus this procedure permits check- ing the adequacy of the amplifier pow- er rating; and if this is found lacking, permits establishing how much more power would have been necessary for realistic reproduction.
Experimental Tests
Actual tests were performed using these techniques. Although these were conducted with various speaker and amplifier combinations, the reference speaker system used was the AR-Jans- zen. This was selected, despite its low efficiency, because it was one of the few systems in which the distortion over the entire 20 cycle to 20,000 cycle spectrum could be kept below 5% over the dynamic range anticipated. The efficiency of this speaker combination is between 1% and 2%. Conclusions established with this speaker system can be extrapolated to others by allow- ing for relative efficiencies.
(Continued on page 78)
(B) Amplifier
amplifier would require four times present power capacity to avoid clipping shown.
WALTER H. BUCHSBAUM
Television Consultant RADIO & TELEVISION NEWS
we
Fig. 2. An open-face console, the “Saratoga,” features dual speakers.
Fig. 1. The “Granada,” a table model with side speaker, is the basic set.
Partially concealed controls produce streamlined appearance; a novel channel-tuning lever is used.
certain amount of
standardization is found in every color TV receiver, the 1957 line of Sylvania color models contains a num-
A stancarai a
ber of novel features. Some are elec- trical, some mechanical, and a few are of more interest to the set owner than to the service technician. These fea- tures as well as Sylvania’s price and service policy, will be considered here.
Models and Prices
The basic chassis for all Sylvania color sets is the type #1-534-1, with the major differences between models involving cabinet size, finish, and loud- speaker size. Fig. 1, model 31T304B, the “Granada,” lists at $605.00 in blonde while the same set with the letter suffix “M” for mahogany costs $595.00. These models use a v.h.f. cas- code tuner, but equivalents are avail- able at slightly higher prices for both v.h.f. and u.h.f. reception. The inclu- sion of u.h.f. is indicated by the letter
46
“U” following the set’s model number.
An open-faced console model is shown in Fig. 2. This is the 31C606M “Saratoga” which lists at $695.00 for the mahogany finish and $715.00 for the blonde Korina veneer version. The console has one 4-in. and one 8-in. PM speaker, both mounted behind the cloth-covered baffle board below the picture tube, while the table-model re- ceiver uses < 5%-in. PM speatrer mounted at the upper righi-hand side of the cabinet.
Service Policy and Warranty
Like all TV manufacturers, Sylvania provides a standard 90-day guarantee on all parts and one year for the color picture tube. At the time of writing, no factory service has been offered. The manufacturer relies on franchised dealers for monochrome installation and repair, and expects to continue this policy with color. To enable its distributors and dealers to service
color TV receivers, Sylvania is offering a one-week factory training course for service technicians. The course con- sists of classroom lectures combined with actual work on color receivers. The total of 48 hours of instruction usually gives the student quite a good knowledge of color service.
The independent service technician who is not part of the Sylvania dealer system can get full color TV informa- tion from the manufacturer’s Service Department. Detailed circuit diagrams with voltage readings and waveforms are provided, as well as a booklet ex- plaining color TV and special circuits.
Operating Features
The location of the operating con- trols and the method of channel tuning is probably the most outstanding fea- ture for the set buyer. Channel tuning is performed by means of a lever, which actuates the conventional cas- code turret tuner through a rack-and- gear arrangement and is also linked to a channel number display drum. By pushing the lever to the right a new station is tuned in, but for fine tuning a partially concealed wheel must be adjusted.
The other controls are similarly con- cealed, as can be seen in Figs. 1 and 2. Only the rim of each knob is visible, which gives the appearance of a smooth cabinet without any knobs and dials protruding. Both console and table models have a tone control and only two color controls for the view- er’s use. These are the hue or color phase control and the chroma or color gain control. All other controls and adjustments are accessible from the rear of the receiver.
Adjustment and Operation
To receive a color program, turn the “color” control first to its extreme left position until the switch clicks. Next adjust the monochrome controls for proper contrast and brightness, and make sure that t‘e fine-tuning adjust- ment is correct. in other words, the first series of steps is concerned with obtaining a good monochrome picture.
After this has been accomplished, turn the “color” control slowly to the right until the picture becomes tinted. If colors appear to have the wrong hue
observation of flesh tones will gen- erally provide the most accurate indi- cation—adjust the “hue” control care- fully for the most natural tones. When this is achieved, the “color” control is once more adjusted, this time until all colors are properly bright. Make sure, in this last step, that white objects remain white.
RADIO & TELEVISION NEWS
With the transistor in the output stage, use of these new tubes in auto radios makes possible a vibratorless supply.
E Low Plate-Potential Tubes
Re-evaluation of design parameters led to this new family of tubes for direct operation from a 12-volt source. With a compatible power transistor, they make the elimination of vibrator power supplies in automobile radios possible.
HE development of the transistor by
Bardeen, Brattain, and Shockley of
Bell Telephone Lab. in 1948 started a new phase in the technology of com- munication and electronic instrumenta- tion. The rapid development of tran- sistors provides many challenging opportunities to achieve results here- tofore difficult or impossible with vac- uum tubes.
Of immediate interest are those ap- plications where the special advan- tages of the transistor can be most fruitfully employed. A clear-cut ex- ample is the hearing-aid field, where the transistor inroad is complete. An- other intriguing opportunity is in auto- mobile radios, and this field received early attention from application engi- neers. Many experimental, and a few commercial, all-transistor automobile sets have been made. They have many good features but are presently expen- sive and an adequate, economically practical, supply of the varied tran- sistor types needed for volume pro- duction of such sets is not yet at hand.
Probably the most attractive feature transistors afford in auto-radio design is the chance to eliminate the vibrator power supply. Aside from its cost and the jealous)y husbanded space it re- quires, this facility is a cause of con- siderable field trouble. The car manu- facturers rank vibrators No. 1 among the components needing attention dur- ing the early period of service. Fur- thermore, in doing its job, the vibrator does not suffer in silence. Vibrator noise which is both mechanical and electrical (in the form of r.f. hash and low-frequency hum) is an irritation to
January, 1957
the set designer. His mastery of this problem, often incomplete, also results in minor annoyance to the customer.
A single power transistor providing power output levels that are out of the question with vacuum tubes operating at low anode potentials allows one to discard the vibrator power supply; provided the functions of amplification, heterodyning, detection, and automatic gain control can be fulfilled with vac- uum tubes at low potentials. Whether provision of such functions was feasi- ble has been a hotly debated subject.
Tung-Sol took a lively interest in this matter shortly after March 1952 when the Lamp Department began work on 12-volt sealed-beam lamps. One of the motor car companies had advised it was changing from 6 volts to 12 volts in its automobiles, princi- pally to obtain better ignition, but also to save some copper. Later, the other car companies made the same switch and furthermore adopted the conven- tion of a negative ground connection. In the past, many makes of automo- biles had the positive terminal ground- ed. This lack of standardization would have been awkward.
Incidentally, the writer has been un- able to rationalize the choice of polar- ity made by different car manufactur- ers, in the past, although he has in- quired extensively of automotive peo- ple. One quaint story was to the effect that a certain ground polarity was re- quired because its opposite caused ground currents returning from the rear axle via the drive-shaft to de- plate the crank-shaft bearings. In any case, the trend just noted opened the
By Cc. E. ATKINS Tung-Sol Electric Incorporated
way for a realistic consideration of a hybrid receiver employing one power transistor and 4 or 5 vacuum tubes.
Most tube engineers were loathe to embark on a tube program for low plate-potential service. There was a history of unhappy consequences when- ever set designers tried using tubes at too low an anode potential. For in- stance, during the war the 6AJ5 was designed in a hurry because the 6AK5 proved unusable in production com- munication equipment running at 28 volts, even though this type had been used successfully in a pilot run. There was an old rule of thumb to the effect that the mw of a tube must always be less than the plate potential. Oper- ating difficulties were sometimes en- countered with triodes having a mu of 100 operating in a.c.-d.c. sets with anode potentials of 80 to 100 volts.
If one attempted to use much bias on the tube, the plate current would be cut off. This sometimes happens in practice. Because of this, some engi- neers expressed the offhand opinion that practical tubes at 12 volts £, must have an amplification factor, or mu, of less than 10. They felt that, since the grid bias had to be approxi- mately —1 volt (due to contact poten- tial), there would be no plate current if the mu were higher than this value. Although the mu decreases rapidly as the plate voltage is reduced below 20 volts, it is possible to have an appre- ciable plate current and Gn, under these conditions.
In fact, one is surprised that the I, is higher than a prediction based on the tube’s characteristics at 100 volts would lead one to expect. From in- spection of the plate families of the type 12AJ6 (a diode-triode) at high and low plate voltages respectively, it can be seen that the mu, which was 112 at 250 volts, drops to 50 in the neighborhood of 10 volts. Fig. 1 is a dramatic display of this effect, where the mu of the 12AJ6 is shown to drop
47
4
CURRENT I, #2.
| | |
10 20 Ke) 4 SO 60 PLATE VOLTS
Fig. 1. Change in mu of triode section
of the 12AJ6 as plate voltage changes.
“Sr Ip VS Ef TYPE 12CR6
‘¢ mn |
F Oe
Ec, ADJUSTED FOR Ip =..5 MA. AT Ep'= 12V. - Esupply = I5V.
PLATE Ip MILLI AMPERES
8 ote Ve oe HEATER VOLTS
Fig. 2. Control-grid resistance (Rc:) affects change of I, vs heater voltage.
from 77 to 50 volts E, to 15 at 1.5 volts E,. The plate current was held constant at the different values of E, in taking this data.
It is believed the reason for this phenomenon is that, as the grid bias approaches zero, the potential mini- mum which is normally at or very close to the cathode moves over in the direction of the grid plane. This changes the effective geometry of the tube, thus lowering the mu. Also, the initial velocities of the emitted elec- trons are more nearly comparable to the accelerating field due to the plate
at these low anode potentials. This un- doubtedly modifies the behavior of the tube.
Another serious pitfall was thought to be contact potential. Since this would establish the bias at which these low-voltage tubes would operate, many engineers felt that variations of contact potential between different production lots (or during life in the same tube) would seriously affect the performance of any equipment using them. Contact potential had been the villain in many an ill-fated marriage of tube and circuit. However, a deeper insight into the inter-relation between contact potential and other tube pa- rameters revealed how it might he possible to exploit the very feature that generated the apprehension.
One facet of this many-sided situa- tion is depicted in Fig. 2. This is a plot of plate current vs heater voltage in the 12CR6. By shifting the screen voltage for each value of control-grid resistor, it is possible to adjust J, so that it is always .5 ma. with 12 volts on the heater. Hence, all the curves intersect at this point. Note the dra- matic difference in slope between the condition of zero grid resistor and that where 10 megohms is employed. Even using 1000 ohms makes a considerable improvement. These phenomena stem from the fact that with higher heater voltage (and consequent greater cath- ode temperature), more current flows to the No. 1 grid because of the greater velocity possessed by the emit- ted electrons. Of course, more current will go to the plate and other elec- trodes as well.
If the resistance in the grid-to- cathode path is low, there can be no change in grid potential as the grid current increases. If this grid resist- ance is high, the grid develops a nega- tive voltage which will increase with increasing cathode temperature. This rising voltage at the grid will prevent the more energetic electrons from reaching the plate. Hence, there is a kind of compensation which, as Fig. 2 shows, tends to hold the plate current more nearly constant. In the same manner G,, and other tube character-
| 39.0
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POWER OUTPUT
Fig. 3. Power output in milliwatts of several tube types. Only the newly de- veloped 12K5 comes close to providing the drive needed by the power transistor.
R, OPTIMIZED FOR EACH TYPE
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6AUS_26A/ 6ASS_6AQS_GAKE
istics are leveled out as well. Also, this compensation affords a measure of bal- ance when the effective cathode area or the cathode activity changes. At Tung-Sol, several new tube designs have been evolved embodying this principle.
In the composition of a hybrid auto set, there appeared to be these prob- lems the tubes must solve:
1. Driving the power output trans- istor: This step required a shift from voltage amplification to current ampli- fication, calling for some power output from a vacuum tube. It was estimated this might be as much as 50 milli- watts.
2. Getting gain: Voltage amplifica- tion could use either low-impedance or high-impedance circuitry. The earliest endeavors .ook the form of tubes with larger cathodes giving higher G,, at the price of lower R, and greater grid- plate capacitance. After some prelim- inary experimentation, this approach was temporarily side-tracked because the conventional tubes with lower Gn but high R, and low C,, appeared to give a quicker answer. Already de- signed if. transformers could be used, and some early sets were made using standard tubes selected for the best low-voltage operation. As a matter of fact, while the design of most of these tubes has undergone considerable revi- sion, one of them, the 12AJ6, remains unchanged. It is merely a 12AV6 with special processing, tested under the low-voltage conditions.
3. The a.g.c. problem: The fact that the input signal at the first r.f. grid is commensurate with the plate voltage posed some new and nasty problems.
4. Stability of gain: Since 12-volt auto sets are expected to function ef- fectively at supply voltage from 10 to 16 volts inclusive, this apparently he- roic requirement had to be met. Good life is also required under these con- ditions.
Returning to problem 1, the trans- fer of power, it was felt 50 milliwatts might be needed to drive the transis- tor. Whether this will remain so de- pends, of course, upon the power gain of available transistors. In some re- spects, a suitable driver tube is the keystone of a successful hybrid radio set.
As Fig. 3 shows, conventional tubes, even relatively high-power examples, are inadequate to do the job. Only the newly developed 12K5 comes anywhere near the power-output objective. The availability of peak current approach- ing 40 milliamperes in the vicinity of zero bias is achieved in the 12K5 by employing the structure depicted in cross-section in Fig. 4. The plate fam- ily and transfer characteristics ob- tained with the special design are shown in Fig. 5.
In the 12K5 the space-charge grid principle is employed. This was first disclosed by Langmuir in 1913. By providing a No. 1 grid adjacent to the cathode with a positive accelerating potential applied to it and a control grid disposed between this accelerator
RADIO & TELEVISION NEWS
and the plate, Langmuir was able to make tetrodes with very high trans- conductance. When screen-grid tubes became commercially available after 1926, sporadic efforts were made to use this principle in equipment. How- ever, most of the tetrodes and pen- todes available to the equipment de- signer did not operate well under space-charge conditions. Furthermore, it was not good engineering economics to provide the power required by the space-charge grid, as the gain in trans- conductance did not generally warrant the cost entailed in exploiting it.
But in a car radio there is a differ- ent kind of logic. Since the voltage is low, it is easily provided by the car- carried battery. The 50 or 100 ma. re- quired for the space-charge grid is minuscule in the over-all current needs of the modern automobile. Ac- cordingly, this ancient stratagem, long discarded, was revived for the tube that became the 12K5. The geometry of this type provides a fine-pitch No. 1 grid having 150 turns-per-inch spaced .018” from the cathode, which is fairly large, with an area of 1.8 square centi- meters. The grid-to-cathode spacing is generous and poses no manufacturing difficulties. The No. 2 or control grid, having 80 turns-per-inch, is a _ bit closer to both No. 1 grid and plate. Here the spacing is approximately .012” each way. Holding this configu- ration is a bit tricky in production.
This disposition of elements provides the desired features. It is believed that the fine No. 1 grid to which the 10- to 16-volt car-battery potential is applied accelerates the electrons and groups them into thin sheaths. It is well known that the factor that limits cur- rent in thermionic devices is the re- pelling effect of the electrons upon one another when they are crowded to- gether. The provision of a multitude of layers where the space-charge den- sity is low probably helps to achieve high space currents with low applied potentials. In addition to its power- output performance, the 12K5 is an ex- cellent low-voltage relay control tube. It is possible to achieve 8 or 10 ma. of plate current with only 2 volts of plate potential.
As mentioned earlier, providing ade- quate automatic gain control was a real problem. The usual a.g.c. poten- tial has a magnitude comparable to the anode potential of the if. ampli- fier. This is insufficient to protect the No. 1 grid of the first stage against positive excursions on very strong sig- nals. Accordingly, there is bound to be spill-over through the first stage, and this can be sufficient to overload the converter tube. However, design- ers hit upon the expedient of applying additional a.g.c. voltage to the sup- pressor grid of the r.f. tube in order to limit the amount of signal getting to the following stage. To do this suc- cessfully, certain compromises have been forced on the tube designer.
With high impedance i.f. transform- ers, it is necessary that the amplifier tube have a correspondingly high dy-
January, 1957
~
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=
#1 OR SPACE-CHARGE GRID
POL
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#2 OR CONTROL GRID.
Fig. 4. Location of special space-charge or accelerating grid in 12K5 tetrode.
namic plate resistance (R,). This has been difficult to achieve in tubes oper- ating at low anode potentials. The beam-forming plates and suppressor grids, which are effective in high po- tential devices, do not give the same favorable results with operating po- tentials in the region of 10 to 15 volts. In fact, the suppressor grids employed in these hybrid r.f. tubes are probably more useful in reducing the control- grid-to-plate capacity than they are in providing effective suppression.
The R, of a tetrode is considerably influenced by secondary emission from the anode. These secondary electrons leave the plate and are collected by the screen grid. Since the magnitude of this effect is sensitive to the applied potentials, a condition exists whereby small increments of anode potential can cause either a drop in plate cur- rent or too rapid a rise in plate cur- rent. In the latter case, R, will be too low whereas, in the former case, it will be negative. Either of these effects can be harmful. On many tubes it was found that a nice balance between negative and positive R, along the plate volt-ampere curve resulted in R, values which were astonishingly high (several megohms where, without this effect, the R, would have been a few hundred-thousand ohms).
This dip in the characteristic is shown in the curves for the 12AD6 in
Fig. 6A. Those readers who are old enough to remember the early screen- grid tetrodes (type 24A), will recog- nize this shape as the dynatron kink. Pentodes were introduced to cope with this characteristic. A coarse-pitch No. 3 grid placed between the screen grid and the plate served to thwart the re- turn of electrons from plate to screen. Because of the geometry involved, this grid did not adversely affect the flow of primary electrons to the plate to any great extent. As stated earlier, suppressor-grid techniques do not function as well with tubes at low voltages. While suppressor grids are still used in the hybrid-set tube de- signs, it is mainly to help reduce the grid-plate capacity and because this grid is sometimes needed to secure adequate a.g.c.
It was found necessary to rely on special materials and processing in or- der to iron out the plate characteris- tic and secure the needed control over the R,. The efficacy of these measures is-greatly facilitated by the important fact that these tubes are used at very low voltages, so that there is very lit- tle plate or screen dissipation. The heat developed by the electrodes in more conventional cperation has the effect of disturbing or destroying any surface film left on the electrodes by special processing. In contrast, it is
(Continued on page 130)
Fig 5. Characteristics of the 12K5 obtained with construction shown in Fig. 4.
50
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(8)
for 2-way Speaker Operation
By ROBERT G. VAUGHN
Details on a simple two-stage circuit designed to be used as a high-frequency amplifier for improving reproduction.
N THE operation of systems using separate speakers for high- and low- frequency ranges, commonly known
as “woofer-tweeter” combinations, it has been standard practice to accom- plish separation of frequency bands in the low impedance circuit between the output transformer and speaker voice coils. The low impedance makes this circuit unwieldy for the purpose and imposes practical restrictions and dis- advantages.
There is a distinctly better method of operating such a speaker system which has advantages unobtainable with other methods as well as impor- tant features which have nothing to do with crossover, networks. The as- sumption that a separate high-fre- quency amplifier would be much more expensive than an adequate low-im- pedance dividing network is unwar- ranted because it overlooks a very important fact. This is that an ade- quate high-frequency amplifier may be small in comparison to the wide-range amplifier already in operation and may cost just a fraction of the price of the larger unit. The reason, of course, is the reduced power requirements in the high-frequency range.
Experiments made with simple rec- ord playing equipment show that a
minimal two-stage amplifier with a single output tube, such as a 6V6, is adequate as a high-frequency ampli- fier when used in combination with a main amplifier of about 20 watts out- put. These tests showed that with this method a worthwhile improve- ment is realized even without using a special high-frequency speaker, irre- spective of the pickup used. It may be applied to any existing system having an amplifier and speaker system which performs satisfactorily at low frequencies.
With this method, frequencies above approximately 800 cps are diverted from the main power amplifier into the high-frequency amplifier and fed to a separate speaker, which may or may not be especially designed for this purpose. A simple filter attenuates frequencies above this point at the rate of 6 db per octave in addition to any equalization present, before they get into the main or low-frequency amplifier. Frequencies below 800 cps are attenuated so rapidly in the high- frequency amplifier they soon drop out altogether. In its design, none of the special precautions necessary for low-frequency power amplification have to be considered. An inexpe:.sive output transformer will be entirely
Circuit of the high-frequency amplifier which covers range from 800 to 30,000 cps.
R:—500,000 ohm pot (“Gain control”) ci Re—10 megohm, '/2 w. "
res. ai Rs—27 ohm, 2 w. res. GAIN 7 Ri—100,000 ohm, 1 w.
res.
Rs—220,000 ohm, 2 w. © res.
Re—250 ohm, 10 w. wire- wound res.
R>—680 ohm, 2 w. res.
(see text) = Re—470,000 ohm, 2 ».
res.
Cr—250 pufd. mica ca- pacttor
Ce, Cs—2000 pyufd. mica capacitor
Cr—10 pfd., 25 v. elec. capacitor
|
\
Cs, Co—20 pfd., 450 +. elec. capacitor
7 V.AC, ¢
Ce] Se
Cr—.05 ufd., 400 ». ca- pacitor
Cr—.002 afd., 400 v. capacitor
CH:r—10-15 hy., 65 ma. filter choke (Stancor 1708 or equiv.)
Tr—Output trans., 5000 ohms to voice-coil (Stancor 3830 or equiv.)
2 7 vi v2 FILTER
T:—Power trans. 275-0-275 voits @ 65 ma.; 6.3 volts @ 1.3 amps.
Sr—S.p.s.t. switch
Jr—Phono jack
Vir—6S75 tube
Vi—6V6 tube Ve—6XS tube
ene eee
satisfactory and only the _ simplest filtering is required.
The possibility of intermodulation distortion virtually disappears because no large low-frequency voltages are present in the high-frequency ampli- fier. The large low-frequency noise voltages developed in record repro- ducing equipment never get into the high-frequency amplifier at all. The separate gain controls for each am- plifier afford complete and exact con- trol of power supplied each speaker without any possibility of interaction between the units.
Reference to the circuit diagram of the high-frequency amplifier used in these experiments shows it to be al- most identical to any other two-stage, single-ended-output audio amplifier. Actually, there is a world of difference in its performance and this is due, al- most entirely, to the values of coupling and input capacitances. The input im- pedance corresponds to 250 upsfd. in series with 500,000 ohms. Thus it may be connected directly to any crystal or ceramic pickup with virtually no effect on its response. In the case of a variable reluctance or any other type pickup requiring a preamp, it is con- nected at the preamp output. Little, if any, advantage is sacrificed because of this necessity. Equalization remains exactly as before.
In all cases, the simple high-fre- quency filter shown in the diagram is connected at the input of the main amplifier. The values given assume an input impedance of 500,000 ohms. There will be an insertion loss of 6 db whick cen be tolerated in most cases. No changes whatsoever are required in the amplifier itself if its low-fre- quency power response is at all satis- factory.
The feedback resistor, R:, was chosen to give 10 db of feedback with a Stan- cor 3830 transformer, using the entire secondary. With any other transform- er, its value may be different and must be determined by experiment.
While there may be an advantage in using a special high-frequency speaker if one with a cut-off below 800 cps is available, it cannot be said to be ab- solutely necessary. It is obvious that the importance of speaker efficiency, if not of. range, is less with this sys- tem because, within limits, it may be compensated by adjustment of the high-frequency gain. It was found that an ordinary 12-inch speaker without any sort of baffle (which, incidentally, may be entirely neglected if desired above 800 cps) gave quite satisfactory performance. The advantage of the wider angle of projection of exponen- tial horn speakers may be important in many cases, however. The most pleasingly realistic and surprising re- sults were obtained, as might be ex- pected, with a wide separation of speaker, as wide as the room permit- ted, about 20 feet. It is a simple mat- ter to hang a speaker in a far corner of the room, for appearance sake it may be mounted on a small panel, and
(Continued on page 147)
RADIO & TELEVISION NEWS
RADIO & TELEVISION NEWS
January, 1957
hangover from the early days of re-
production, before electrical meth- ods of recording were introduced. The tone arm was the swiveling channel that conveyed the sound waves gen- erated in the sound box to the horn that was the acoustic phonograph’s counterpart of the modern loudspeak- er. It literally conveyed the tone from the sound box to the horn. Reproduc- tion has come a long way since those days!
Early experimental electrical pick- ups were first strapped to the tone arm of an acoustic phonograph as a quick and ready means of giving the new idea a tryout. Hence when arms began to be designed specifically for carrying the pickup, it was only nat- ural that the old name should be car- ried over to the new part.
Even the first electrical reproducers were a considerable improvement on the acoustic systems, because they made available extended frequency range and considerably reduced the peakiness of the reproduction. But those early electrical pickups were a far cry from the modern high quality product. High fidelity is an ideal hob- by for the perfectionist. Better loud- speakers, better amplifiers, better pickups—each in turn receives atten- tion with a view to approaching per- fection.
As the quality of loudspeaker units improved, it becarne evident that the enclosure in which the loudspeaker was mounted plays an important role in the quality of reproduction. Early arms for carrying pickups were, like early loudspeaker enclosures, merely regarded as a means of holding the electrical unit so it could do its job. But modern developments have shown that attention to the design and con- struction of the tone arm is as impor- tant to successful pickup from a rec- ord as attention paid to the design of an enclosure is to reproduction from a loudspeaker.
In each case it is at the low-fre- quency end of the spectrum that the means of mounting—in the case of the loudspeaker, the enclosure, in the case
ic name “tone arm” is really a
January, 1957
By N. H. CROWHURST
49
How to pick right unit for your particular high-fidelity
system and discussion of most important factors involved.
of the pickup, the tone arm—influ- ences the over-all response of the sys- tem. In fact, a tone arm has to per- form several functions satisfactorily to give good reproduction under all circumstances.
While there is a variety of extreme- ly good tone arms on the market, it is not possible, at present, to pick out one as being “best” in all respects. Each model has its good features and its bad points. The best we can do here is to outline the requirements and the purposes served by different features in a tone arm so that each reader can select for himself the com- bination of characteristics that will best serve his purpose. To tackle this, we will take different features in turn and point out the pros and cons of each.
Long or Short Arm?
This question is principally linked to the problem of tracking, that is, mak- ing sure the direction of stylus travel is always perpendicular to the groove. If it is not perpendicular to the groove, then the way in which the stylus moves in tracing a sine wave along the groove will no longer be sinusoidal, but will take the form shown in Fig. 1A. Fig. 1B shows how this waveform can be synthesized from the funda-
Fig. 1. (A) Output from pickup cartridge when movement of stylus is not at right angles to direction of groove and (B) the waveform synthesized by a fundamental and a second harmonic. Refer to discussion in the text.
mental and a second harmonic com- ponent.
Thus, failure to track correctly will introduce a component of second har- monic distortion proportional to the error of tracking angle from the true perpendicular, or 90 degrees. In addi- tion to harmonic distortion there will be intermodulation distortion when more than one frequency is present, as is the case with practical record- ings. All tone arm manufacturers sup- ply necessary instructions, and usual- ly a mounting jig, to assist in making sure that the tone arm is correctly mounted to obtain minimum tracking error. But a simple explanation of how tracking error is reduced to a minimum for a given length of arm will serve two purposes here: it will help to get a clearer picture of why the correct mounting position is so im- portant; and also it will show exactly the effect of tone arm length on this tracking problem.
Records are made with a cutter head that travels on a lathe mech- anism at right angles to the groove, as shown in Fig. 2A. This insures that the modulation recorded in the groove is at right angles to the direction of the groove, throughout the recording. A hinged tone arm can only produce an approximation of this ideal at the reproduction end.
First consider a straight tone arm with the stylus mounted so as to move at right angles to the line of the tone arm as shown in Fig. 2B: for any par- ticular radius of groove the tone arm can be mounted so as to give the cor- rect movement, as shown by the solid line position; but as soon as the tone arm moves from this set radius, the tracking is no longer true—the angle of movement is no longer at right angles to the direction of the groove,
Fig. 2. Approaches to tracking. (A) In recording, the cutter head traverses a bar along a radius of the recording, which gives true tracking at all points. (B) A straight arm can only achieve correct tracking at one point, represented by the solid line. Dotted lines represent other positions that depart from correct track- ing. (C) An arm with the pickup mounted eat an angle can achieve correct tracking at two points, as shown here; keeps much closer than a straight arm for rest of its traverse. This matter is covered in text.
as illustrated by the dotted lines in Fig. 2B.
It is impossible, using an effectively straight tone arm, to produce correct tracking at more than one radius on the record.
Notice that the direction of devia- tion from correct tracking is the op- posite way, depending on whether the radius is larger or smaller than that for which the mounting is correct. By using a curved arm, or having the pickup mounted at an angle on the end of a straight arm, it is possible to set the pivot so that the tracking is correct at two different radii during the playing of the record. This means that the deviation from correct track- ing will be considerably reduced throughout the entire recording as illustrated in Fig. 2C.
The new relation can be better un- derstood by referring to the diagrams of Fig. 3. Fig. 3A is a repetition of the method of mounting in Fig. 2B to suit one particular radius. The solid
Fig. 3. A demonstration of the geometry in- volved in the tracking problem. (A) Straight arm, with single correct position. (B) Bent arm, single correct position. (C) Bent arm with modified mounting to give two correct positions. (D) Longer bent arm, showing reduced deviation from accuracy over the entire range of movement. Refer to Fig. 2.
radius shows the actual movement of the stylus point with the tone arm pivoted at the position shown. The dashed-line radius going through the same point shows a stylus point move- ment that would be necessary, holding the line of the arm through the same pivot point, for tracking to be main- tained throughout the recording. This would, of course, necessitate an arm that changed its length as it pivoted around its fulcrum. Notice that this deviation is in the opposite direction on either side of the central point.
In Fig. 3B is a similar construction for the head mounted at an angle as in Fig. 2C. In this construction the tracking is arranged to be correct at the central point and two curves are again drawn to show the actual move- ment about the pivotal point and the required movement using the same pivot to maintain correct tracking. Notice, in this instance, that the de- viation in length of the arm on each side of the central point is in the same direction, instead of in opposite direc- tions as in Fig. 3A.
By making a slight adjustment in the pivot point, as shown in Fig. 3C, the tracking is slightly incorrect at the central radius, but becomes cor- rect a little distance on either side of it. In this way a minimum error can be achieved throughout the whole playing band of the record.
Now compare Fig. 3C with Fig. 3D which represent the same method of mounting with arms of different lengths relative to the diameter of the record being played. Notice that the shorter arm, represented by Fig. 3C, shows greater deviation from correct tracking than Fig. 3D, as represented by the spacing between the two curves over the width of the record band to be played.
Now we are in a better position to answer the question about the length of the tone arm. To maintain the nearest approach to correct tracking through the whole band of recording, the longer the tone arm the better. Whatever its length, however, the best tracking will be achieved:
(a) by having the pickup mounted at an angle relative to the tone arm pivot so that the stylus movement is perpendicular to the line joining the center of the turntable to the tone arm pivot at a point approximately in the middle of the playing band of the record, as shown in Fig. 4.
(b) by setting the pivot slightly for- ward from the position for correct tracking in the middle of the record band, so as to give perfect tracking at two points, a little in from the ex- tremities of the band.
This means that to obtain the best possible playing over each of the dif- ferent size records available, the angle of pickup mounting should be altered to suit. However, by using a longer arm, and regarding the total playing bandwidth as being from the largest diameter on a 12-inch disc to the smallest diameter on any kind of disc played, the best compromise can be
RADIO & TELEVISION NEWS
achieved for playing all kinds of rec- ords without having to change the angle of pickup mounting and the po- sition of the tone arm pivot.
Ten-inch and twelve-inch discs are, to some extent, interchangeable as’ re- gards groove modulation, having both the old 78 rpm groove and the micro- groove or 33% rpm so it is not prac- ticable to make different mountings for each of these diameters. On the other hand, for equipment designed to play only the smaller 45 rpm discs it is feasible to use a shorter arm with the pickup mounted at an angle to suit the playing of this particular disc.
This means that a_ considerably shorter arm is practical for operation on a unit designed to play 45 rpm discs only. For the more usual type of equipment, designed to play all three different speeds, the practical solution is an arm and pickup mount- ing that is common to all sizes of disc: it is hardly practical to make a mount- ing for the 45 rpm pickup at a dif- ferent angle and radius from the pivot than the pickup used for 10-inch and 12-inch records. But the use of a longer arm will insure a closer ap- proach to correct tracking throughout all of these records.
The problem that sometimes occurs with a long arm is that of getting it into the cabinet chosen: a longer arm necessitates a larger space to get the pivot in the correct position, and hence a larger cabinet to enclose the whole mechanism.
Straight or Curved?
This question is closely linked with the previous one and is, to some ex- tent, a matter of esthetic choice. The important thing is that the pickup should be mounted at the correct angle to suit the length of arm and the mean diameter of the groove to be played; whether this angle is achieved by utilizing a curved arm with the pickup mounted straight on the end of it, or by using a straight arm and mounting the pickup at an angle, is immaterial from the viewpoint of achieving correct tracking.
Some prefer the curved arm for psychological reasons, because the angle of the arm tip is in line with the direction of the groove where the stylus rides in it, and this seems more logical.
On the other hand, the straight arm can sometimes save space, as illus- trated in Fig. 5. When the arm is at its position of rest, with the pickup parked outside of the record diameter, the greatest distance from the turn- table, apart from the pivot itself, will be the outward curve of the arm. This will mean that the dirmensions of the motorboard will have to be extended in two directions instead of just the one necessary to include the pivot in a corner. The straight arm allows one dimension to be smaller than is pos- sible with a curved arm of the same length. This is probably only a mat- ter of an inch or two and may not al-
RADIO & TELEVISION NEWS
ways stance: betwee arm ir
This tone a tween The pi of the vertica which the pi reduce appliec which
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To f ern pi force o groove tone a up and warpin ciably course, some e tia of 1 of an vertica pickup for hor
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.
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January
January, '757
ways be important, but in some in- stances it may make the difference between fitting or not fitting a certain arm into a certain cabinet size.
Pivot Construction
This is another feature in which tone arm practice differs widely be- tween one manufacturer and another. The pivot allowing vertical movement of the pickup may coincide with the vertical pivot of the tone arm, about which it turns, or it may be nearer the pickup. The latter arrangement reduces the vertical inertia effectively applied at-the pickup stylus point which can prove advantageous.
All pivots should be as free from friction as possible, because any fric- tion will be liable to impose distortion on the system. Friction is not to be confused with viscous damping, which merely limits the speed at which move- ment can take place.
In considering the general mechan- ical construction and positioning of the pivot, the important factor to re- member is that the pickup is only re- quired to move very slowly laterally, as it follows the spiral groove from the start of the record to the end. With modern recordings allowance is not necessary for eccentricity of the groove, because this would produce a very definite wow. For this reason, recordings must be made with the cen- ter hole well centered so the groove is a true spiral. On the other hand, re- cordings do sometimes warp to some extent so that the pickup has to go up and down as the record rotates.
To follow the groove, an ideal mod- ern pickup may only need a stylus force of about 1 gram to keep it in the groove and maintain tracking. The tone arm should be so designed that up and down movement, due to slight warping of the disc, does not appre- ciably modify this stylus force. Of course, it is bound to modify it to some extent, due to the vertical iner- tia of the arm. This is the advantage of an arm where the pivot allowing vertical movement is nearer to the pickup head than is the tone arm pivot for horizontal movement.
For some applications another fac- tor requires consideration. This is when the system is subject to vibra- tion or movement, as, for example, if it is to be played in a vehicle while traveling (can this be high fidelity ?!). Under these circumstances the arm needs to be dynamically balanced for beth vertical and horizontal move- ment, so that jolts will not jerk the stylus out of the groove or produce undue stress on it. This is a some-
what special application, but if you °
are thinking of it, attention is neces- sary
Arm Shape and Structure
It may be thought that provided the arm has suitable mechanical charac- teristics, as described previously, its
actual shape is immaterial. In prac- tice, however, its-mechanical perform- ance is largely dependent on the shape ind construction of the arm.
January, 1957
The important thing from the view- point of over-all frequency response is the low-frequency resonance that a tone arm can contribute to the per- formance of the pickup. This res- onance is caused by the movement of the arm as driven through the com- pliance of the pickup. One resonance at least is unavoidable, this is a res- onance produced between the compli- ance of the pickup movement and the mass of the arm, moving laterally as a whole.
Careful choice of the pickup and arm combination can put this res- onance at a position in the frequency response where it will be unimportant, but bad design of the tone arm can result in additional resonances. These may cause trouble and arise due to the fact that the arm does not always vibrate as a whole, but sets up sub- sidiary resonances at much higher fre- quencies. Any arm that has the same cross-section throughout its length is more liable to set up multiple vibra- tion as harmonics of its natural vibra- tion, some of which are shown in Fig. 6, and thus contribute irregularities to the response not inherent in the pickup itself.
This is a general argument in favor of an arm with a tapered structure, wider at the base or pivot end, and narrowing down to a smaller section where the pickup fits on to it.
An important feature in choosing a pickup and tone arm combination is to ascertain that the fundamental res- onance does not occur in the region of 30 cycles, which is the frequency where most turntables generate their rumble. The resonance can be quite pronounced and could amplify the rumble considerably. It is also un- desirable that the frequency should be above 30 cycles as this will produce unnatural accentuation of low fre- quencies in the program material. The best position for the resonance is be- low 30 cycles and, if possible, well below, that is, below 20 cycles.
The major possibility of damping this resonance is, of course, in the design of the pickup itself, because the arm is moving as an entire mass and has to have freedom of pivot move- ment in order to allow the pickup to track. However, viscous damping can help reduce its amplitude. But the principal possibility for damping the resonance is in the compliance of the pickup.
Usually the damping of the pickup
Fig. 4. Detailed diagram showing how the correct arrang
PIVOT PLACING FOR SINGLE CORRECT POINT PICKUP MOUNT ~ LINE FROM TONE ARM = ” “pivOT T> STYLUS PONT
PrvOT PLACING n AS FOR TWO COR- “ors FRoy RECT POINTS "ume 7
ACTUAL ARC CORRECT AT Two POTS
SS —
| ! | | fun la
Fig. 5. How an arm with angled mounting for pickup (A) can save space in comparison with curved arm (B) of same length. The dif- ference is shown dotted in (B) of diagram.
STYLUS
STYLUS ~
Fig. 6. Modes of tone arm resonance. (A) Basic fundamental resonance between the mass of the tone arm and pickup compli- ance. (B) First overtone resonance in the tone arm itself and (C) second overtone.
is designed to achieve the correct re- sponse at the high end of the band. It is not feasible to adjust the pickup damping so as to achieve perfect re- sponse at both ends of the band, so careful choice of tone arm is the best solution.
A simple way of checking for the low-frequency resonance effect is to use a 78 rpm frequency test disc, with frequencies from 50 cycles upwards, and run the turntable at 33 rpm which will reduce these frequencies to the region of 20 cycles. Comparison of the response to different frequency grooves will then show how much peaking effect the tone arm and pickup exhib- its. This will enable different combina- tions to be checked and a suitable choice to be made.
The writer does not expect that you will be able to find a combination without any resonance at all. The thing to look for is a resonance that does not color the program material appreciably nor produce distortion due to any vibration that might occur at this frequency.
What About Viscous Damping?
As far as playing is concerned, vis- cous damping is usually unnecessary. It will seldom be adequate to damp out the low-frequency resonance, so its primary purpose is as a safety pre- caution against dropping the stylus onto the platter with undue force, which might damage either the stylus or the stylus arm in the pickup. Vis- cous damping insures that, if the arm is dropped, it descends to the record at a slow rate and with insufficient impact to do any damage.
If the arm is only to be used for
(Continued on page 143)
Se
RADIO & TELEVISION NEWS
Front panel view of high fidelity control unit. Dual controls are used to simplify appearance.
High fidelity audio preamp with seven inputs, tone, level, loudness controls, and five equalizations settings. Rumble and scratch filters are also included.
their high-fidelity systems progres-
sively now have a new master-con- trol preamp kit available for consider- ation, the Zico Model HF-61.
Designed to be used with any high quality amplifier, the new preamp is housed in a handsome cabinet measur- ing 4%” wide, 12%.” long, and 4%” high. The circuit is so designed that the unit may be used separately or may be built-in by removing the hous- ing.
There are two unique and outstand- ing features which have been incor- porated in the design of this preamp. The first involves a new feedback type control for bass and treble tone ad- justments. The circuit provides low distortion and wide frequency range yet the controls do not affect the vol- ume nor interact on each other. As turnover at both ends \ ries with the amount of boost and attenuation, boost or cut at the extremes of the audio range is possible without affecting the mid-range. Neither of these controls affect the tape output jack.
One novel feature of the tone con- trol circuit is that the midpoint (flat response characteristic) is not sharp in its adjustment. There is actually a range of rotation about the midpoint where flat response can be obtained.
The second unique feature is the loudness control, a Centralab ‘“Com- pentrol” unit which raises or lowers the volume in strict accordance with the Fletcher-Munson curve. This con- trol is quite effective; for flat over-all response the loudness control should be set at maximum.
As the control is turned counter- clockwise from maximum clockwise
A weet nien-na who are assembling
54
rotation, not only does the volume decrease, but there is an increasing emphasis on the bass and treble in accordance with the Fletcher-Munson configuration. An uncompensated level control is also provided to permit the proper operation of any system.
A feature unique with kit-type pre- amps is the inclusion of built-in high- and low-end noise elimination filters. These filters are not only valuabie when listening to worn records or poor program material but are especially important in tape recording.
The flat positions of the filter con- trols should be used in direct listening to clean records played on high-quality turntables or cleanly recorded or live AM broadcasts.
It is interesting to note that the fil- ter circuits provide relatively sharp cut-offs whereas the tone controls pro- vide gradual, frequency-proportional changes in the response. One type of control is not a substitute for the other, however, and both may be used to achieve any desired response. It is worth noting that the “variable turn- over” tone controls employed in the circuit may be used to further sharpen the cut-off if desired and in order to shift the cut-off frequencies in either direction.
According to the manufacturer, fre- quency response of the preamp (at the 3 volt level) is + 1 db from 8 to 100,000 cps and + .3 db from 12 to 50,000 cps. The IM distortion (60 and 6000 cps, mixed 4:1) ranges from .2 per-cent at 5 volt output to 1.5 per-cent at 5 volts. Harmonic distortion is less than .82 per-cent from 20 to 20,000 cps at the 3 volt level.
Equalization for RIAA, Columbia,
London, European 78’s, and American 78’s is provided on the input selector switch along with positions for tape, TV, tuner, and auxiliary inputs. Tone controls have a range of about 15 db boost and cut at 50 cps for the bass control, and 15 db boost and cut at 10 ke. for the treble control. Hum and noise are 60 db below 2 volts on the low-level phono inputs, and 75 db below 2 volts on the high-level inputs.
Rumble and Scratch Filters
Reference to the schematic diagram shows that the high- and low-end filter circuits actually consist of dual-section low-pass and high-pass RC networks within a feedback loop. Thus two 6 db per octave turnovers are combined to obtain a final slope that is 12 db per octave, assuming zero input resistance and no output loading. Over-all feed- back is used to control the sharpness of the initial turnover. Filter circuits are inserted in the feedback pair audio amplifier by two front panel 3-position slide switches.
Rumble (low vibration) occurs at about 29 cps in 4-pole record changer and turntable motors and at approxi- mately 58 cps in the inexpensive changers and plavers of the 2-pole va-
riety. Recorded rumble (29 cps) will
also sometimes be found in discs re- corded before the development of the improved techniques in use _ today. Transmitted program material may al- so include such records. Reduced rum- ble is one of the objectives in the de- sign of turntables and changers for high-fidelity use, but the extent to which it is eliminated depends on the quality and condition of the turntable or record changer used. That is why
RADIO & TELEVISION NEWS
wes
Janu
the ru Note | audibl rumbl low-fr systen plifier ble re
Use record to eli rumbl ing he it wit! result. nates ponen provid 50-cps the efi recoré tening off se and h record of se\ as we ers. 7 tions 1 balanc desire based reacti
tening
au
TUNE
PHONO Lo
Janua!
January, 1957
the rumble filter circuits are provided. Note that whether the rumble itself is audible or inaudible (depending on the rumble frequency and the extreme low-frequency response of the speaker system), it may still overload the am- plifier and cause distortion in the audi- ble region.
Use the “50 cps” position whenever recording on tape from records in order to eliminate any trace of subsonic rumble from appearing at the record- ing head and eventually magnetizing it with increased distortion level as a result. The 50-cps cut-off also elimi- nates tape overload from noisy com- ponents below this frequency and thus provides cleaner tapes. In general, the 50-cps cut-off is useful for eliminating the effect of moderate rumble in 4-pole record changers, whether in direct lis- tening or recording. The 100-cps cut- off serves to eliminate noise, rumble, and hum that may be found in older records. It aids in reducing the effect of severe rumble in 4-pole changers as well as rumble from 2-pole chang- ers. The “50 cps” and “100 cps” posi- tions may also be used to restore tonal balance on AM broadcast listening, if desired. The rule for tonal balance, based on a statistical study of audience reactions, is that the product of the extremes of the audie: spectrum re- produced should be about 500,000. Many people feel that full bass re- sponse is more important than tonal balance and ignore such considerations.
The use of the high-end filters to eliminate scratch and high-frequency distortion when recording from or lis- tening to records, and for noise elimi-
Schematic diagram of the Eico HF-61 master-control preamplifier. trol, Rumble and scratch filters are shown in “Flat”
a Q
53
A-OVER-ALL RESPONSE — LOUONESS CONTROL MAX. ar POSITION. Ti TR FLaT T 8- RUMBLE PLLTER - SOCcPS, ALL oma CONTROLS — e ee
c- tooces, 0 -SCRATCH FILTER one. ALL OTHER CONTROLS FLAT - ” ” or ” ” .
ll
20 100 1oKc. 50
iKC. FREQUENCY-CPS Curves showing over-all response of the preamplifier along with both rumble and scratch filter characteristics. It was the above performance which your editors consider most important in the design of this unit. The editors were gratified to note the sharp roll-offs at both ends of the above response curves which we ran. Rumble filter curves are down about 4 and 8 db at 50 cps while scratch fil- ter curves are down about 8 and 15 db at 10 kc. It should be pointed out that due to construction differences and component tolerances, somewhat different fig- ures may be expected on other units. According to the manufacturer, the average figures to be expected are: for the rumble filter, curves are down 6 and 16 db at 50 cps: for the scratch filter, curves are down about 7 and 20 db at 10 ke.
nation from AM broadcasts, will result in cleaner tapes and more enjoyable listening. The “10 ke” position is useful for reducing the annoyance of high frequency distortion and noise from records or broadcasts. The “5 ke” posi- tion is useful for reduction of noise on older or scratchy records, particularly older 78 rpm records, and for elimina- tion of noise above 5 ke. on AM broad- casts.
The preamp will operate on 50 or 60 cycle a.c. at from 105 to 125 volts. The Model HF-61A ($24.95 in kit form) does not include its own power supply but can be driven by the amplifier with which it is used providing the ampli- fier can supply 350 volts at 10 ma. d.c. and 6.3 volts at 1 amp. The Model HF-61 ($29.95 in kit form) has its own self-contained supply. Power consump- tion is only 15 watts.
A Centralab “Compentrol” is used as the loudness con- positions. For other positions, see the table showing shorted contacts.
wei2au?
RUMBLE FUTER
SCRATCH FutTerR
Sifvtal
Oo.
ee Os oe
. CAPACITORS IN LUFO.UNLESS OTHERWISE SHOWN
NOTE: ALL RESISTORS ARE 1/2 WATT UNLESS OTHERWISE SHOWN Au
POWER TRANSFORMER
Ea
@).
4 SELECTOR Swen: 6P 2° (SPOSITION > can SELECTOR Seven sunOens | nm FURTHES CLOCKWISE POSITION, TION |
POSITION eaitee
Switch
pe SCRATCH
RUMBLE FILTER
FuTER
January, 1957
By WILLIAM LEONARD
Two segments of the industry get together to settle past differences, agree on a program.
IGH among the problems that have beset the independent service in- dustry in its efforts to bring about
some degree of stability in the opera- tion of an electronic service business has been its relations with parts dis- tributors. The rapid growth of the bil- lion-dollar electronic service industry while it was tied to a system of dis- tribution that had been created to serve a market made up of radio am- ateurs, experimenters, and radio tech- nicians brought about inequities in distribution that cause continual con- fusion in the operation of a consumer service business.
Spurred by statements made by Jo- seph DeMambro, president of NEDA, to the effect that the National Electronics Distributors Association planned to work with service associa- tions to improve the relations between distributors and the service industry, a meeting was called that brought to- gether representatives of service asso- ciations in Pennsylvania and New Jer- sey. Purpose of the meeting was to formulate a plan for cooperation be- tween the service industry and parts distributors.
The initial program, which detailed ten suggestions for the improvement of jobbing practices and six for the service industry, was sent to service associations in Pennsylvania, New York, New Jersey, Connecticut, New Hampshire, Massachusetts, and Rhode Island for their consideration, sugges-
tions for imprevement, and for rati- .
fication in whole or in part. Subsequently a meeting was held in
Bridgeport, Connecticut, to formalize
the program for presentation to
56
NEDA. This meeting, under the chair- manship of Frank Silverman, president of TELSA of Connecticut, was attend- ed by more than 100 delegates repre- senting associations in the seven northeastern States.
The Bridgeport meeting, termed by the participants as the Eastern States District TV Service Conference, for- malized a program of cooperation that includes’ ten points for the improve- ment of distributor practices and ten points for the improvement of service practices.
Distributor Rules
Titled the “Ten-Point Program for Distributor-Service Relations,” the plan, as it was presented to a NEDA Committee early in December, detailed the following:
Point 1: Parts distributors will ar- range to sell a package deal if the standard discount is to be obtained. All sales under the minimum package deal to be sold at progressively smaller discounts.
Point 2: Development of a system of classification and identification to be issued to personnel (service techni- cians and shop operators) for the pur- pose of obtaining trade discounts. There would, perhaps, be several de- grees of classification and a simple, uniform identification system accept- able to both jobbers and service.
Point 3: Jobbers discontinue the use of repair shops for other than author- ized warranty repairs.
Point 4: Jobbers advise counter, re- pair shop, warehouse, and other help to discontinue the solicitation of serv- ice work as being in competition with
the jobbers’ own servicing accounts.
Point 5: Jobbers should eliminate the use of net prices in advertising and merchandising displays. Only the manufacturers’ list prices should be advertised or publicized.
Point 6: Jobbers should make all published material of an educational nature, and of new and advanced de- velopments in the field, available as soon as possible.
Point 7: Jobbers should make all merchandising displays and related material available to the trade for dis- play in order to assist in obtaining public acceptance of their products.
Point 8: Jobbers should, collectively and as a matter of course, cooperate with all local service associations in sponsoring educational forums.
Point 9: Symposiums and exhibi- tions of all new and advanced elec- tronic equipment should be sponsored jointly by the local service associa- tions and the parts jobbers for the benefit of the local electronic service trade.
Point 10: Eliminate all premium and sales gimmicks and their allied pro- motion.
Service Industry Rules
The following are some of the ways that we in the service industry can be helpful to our parts distributors:
1. Make all purchases from inde- pendent, established jobbers.
2. Discourage the purchase and/or use of surplus merchandise.
3. Refuse to purchase unbranded and bulk tubes and parts.
4. Destroy all defective tubes and parts, unless requested not to do so by our customers.
5. Refuse to accept and return to the sender electronic parts and tubes, mail order catalogues, and similar di- rect mail material which is sent indis- criminately.
6. Encourage service shops to carry adequate stocks of parts, tubes, and test equipment.
7. Refrain from sending retail cus- tomers to wholesale jobbers as much as possible.
8. Lend every support and coopera- tion to jobbers who help to establish local service associations.
9. Cooperate wholeheartedly with any educational program instituted by independent jobbers.
10. Do all that is possible mutually to aid the jobbers in stabilizing the industry.
Immediately after the approval of the dual ten-point program by the del- egates to the Eastern States District TV Service Conference, a committee sent copies of the plan to practically every known association in the indus- try with a request for suggestions and endorsements of the program.
Backed by these endorsements from associations in all sections of the coun- try, the committee for the service in- dustry, headed by Mr. Silverman, presented the program to the distrib- utors’ association as a national service association plan for cooperation. —3Q-
RADIO & TELEVISION NEWS
EIC no) Ele
receive: duces manufa new, li tube, | cuits, compor conduc’ and col The | would tional | elimina ma. ty heater compar from 2 watts, sumpti Beca that se rect pr the eq an imp sign of To this receive: easy a compor lock ty chassis Fig. the rec plus or power tors. EB lator t tuner pentode jor con
January
Design Features of 9° G-E Portables
By JACK NAJORK Field Service Representative General Electric Company
Second-anode lead enters CRT at base rather than through connector on beil.
Removal of wrap-on aluminum cabinet exposes interior parts for service.
Wao tieger less than 13 pounds and
no bigger than a breadbox, General
Electric’s new 9-inch portable TV receiver (models 9T001, 9T002) intro- duces many innovations in design, manufacture, and serviceability. <A new, lightweight, rectangular picture tube, printed and dip-soldered cir- cuits, aluminum cabinet, miniature components, and wider use of semi- conductors contribute to its lightness and compactness.
The prohibitive heat problem which would result with the use of conven- tional 600-ma. heater tubes has been eliminated by the use of the new 300- ma. types. This step alone reduces heater power consumption and the ac- companying heat dissipation problem from approximately 70 watts to 35 watts, and reduces total power con- sumption of the receiver to 70 watts.
Because the average consumer feels that service charges should be in di- rect proportion to the initial cost of the equipment, serviceability becomes an important consideration in the de- sign of a low-cost, compact receiver. To this end, the physical layout of the receiver has been arranged to allow easy access to all tubes and major components as well as the new, twist- lock type of a.c. fuse shown in the chassis side-view photograph.
Fig. 1 shows the block diagram of the receiver which employs 12 tubes plus one tube rectifier, one selenium power rectifier, and five semiconduc- tors. Built-in u.h.f. adds a 6AF4 oscil- lator tube and a mixer diode. The tuner is a conventional 12-position pentode type and this is the only ma- jor component that has not been min-
January, 1957
Use of semiconductors and 300-ma. heater tubes
makes lighter weight and compact size practical.
iaturized for this application. With u.h.f.-equipped receivers, a 13-position v.h.f. tuner is used, together with the added u.h.f. tuner, to provide single- conversion reception.
The two i.f. stages operate at 40 mc. and feed a germanium diode detector which, in turn, drives the pentode sec- tion of the 12CT8 video amplifier. The triode section of this tube operates as a sync clipper, with a.g.c. voltage de- veloped in this stage for application to
the if. and tuner stages. A 10C8 tri- ode-pentode is used as a vertical oscil- lator-output stage; this same _ tube type is also used as a combination first and second audio amplifier. Horizon- tal circuits consist of a dual selenium a.f.c. phase detector, 7AU7 stabilized horizontal oscillator, 18A5 horizontal output, 17H3 damper, and 1V2 high- voltage rectifier. Audio circuits make use of a 6AU6A 4.5-mc. amplifier and (Continued on page 160)
Fig. 1. Block diagram of the G-E 9-in. portable shows how a reduction to only 13 tubes has been achieved by the judicious use of semiconductor devices.
VERTICAL ~
HOR. PHASE DET. HOR. OSC.
- Tee /2 v2 H 10C8 70 YORE - ¢ ie TO
HOR. YOKE OuTPuUT
DAMPER H.V. RECT.
By ALLAN M. FERRES
Over-all view of the control unit and a closeup view of the Clairex CL-2 crystal photocell as wired into the Cinch-Jones plug and as the
t looks — |
ve ‘
ee
The development of this tiny, light-sensitive cell makes possible an interesting variety of compact control units.
teresting subject for the electronic
experimenter. When connected to relays, the number of uses to which it can be put is limited only by the in- genuity of the experimenter. It can be used for such diverse applications as announcing a patient in a doctor’s waiting room, turning on house lights and advertising signs at dusk, auto- matically opening and closing doors, warning householders of intruders, preventing shoplifting, etc. The list seems almost endless, but may now be even further extended with the devel- opment of the crystal photocell.
This tiny cell has several advan- tages over the high vacuum and gas- filled tubes usually employed in pho- toelectric relay circuits. Its charac- teristics are such that light-controlled relays may now be used in applica- tions which are impractical with the conventional photoelectric tubes.
The crystal photocell is a very small device about the size of a lead pencil eraser, 4” in diameter and 1%” long. The light sensitive element is a pure cadmium sulphide crystal which re- sponds to light over the entire visible spectrum. The crystal is a semicon- ductor, its resistance decreasing with an increase in light intensity. Its elec- trical characteristics are such that it may be operated at a considerable distance from the associated amplifier and relay. This factor and its small size make it ideal where concealment of the device is desirable, or where space is limited. The crystal is so
Te photoelectric cell is a most in-
sensitive that operation is practical with normal room illumination when used with a simple amplifier. This eliminates the necessity for using spe- cial exciter lamps and optical equip- ment. In some applications, the relay may be operated directly by the crys- tal itself. Its low cost and mechanical ruggedness make the crystal photocell an ideal device for light-controlled re- lay experiments.
This article describes a control] unit using a simple, basic photocell ampli- fier and relay circuit. Four other cir- cuits are also discussed which will be of interest to experimenters.
The basic circuit, shown in Fig. 1A, is sensitive enough to operate at one- tenth of a footcandle of light. A pro- tective resistor, Ri, the crystal photo- cell, the Clairex CL-2, and the vari- able load resistor, Re, are connected in series across the 117-volt a.c. line. C,, which shunts the load resistor, charges to peak voltage on each cycle to pro- vide a higher striking voltage for the thyratron. The miniature thyratron, its current-limiting resistor, Rs, and the relay are also connected across the line through the switch S:. The relay is a plate-circuit type having a coil resistance of 5000 to 8000 ohms and an operating current of not more than 6 milliamperes and provided with S.p.d.t. contacts. C: shunts the relay coil to prevent chattering. The light, bell, or other device to be operated plugs into receptacle SO;. As a photo- cell relay is usually operated continu- ously, no a.c. “on-off” switch is in-
cluded, but, of course, one may be added if desired, in series with the line cord.
The starter anode of the 5823 thyra- tron obtains its voltage from the volt- age divider made up of R,, the crystal cell, and Re. When the cell is dark, its resistance is high and the starter anode voltage is too low to allow the thyratron to draw plate current. When light strikes the cell, its resistance drops, increasing the voltage across R2z, and the tube conducts. With the switch on, the relay contacts are wired so that the line voltage is connected to the output receptacle only during the interval of time when the light on the cell is interrupted. When the switch is off, a momentary interrup- tion of the light will remove the plate voltage from the thyratron and power will be furnished to the receptacle continuously, even though the light to the cell is restored. This locking type of operation is desirable when the de- vice is used to sound an intruder alarm bell.
As shown in the photographs, the necessary parts can be easily mounted in a 2”x3”x5” case. No ventilation of the case is needed as the power dis- sipated in the unit is less than one watt. The placement of the parts is not at all critical, so any convenient arrangement may be used. Socket ter- minals 2, 5, and 6 of the 5823 should not be used as tie points as these pins are used for internal connections in the tube. The crystal photocell is wired into a Cinch-Jones type P-302- FHT plug. A matching receptacle is mounted on the case, so that the cell can be either attached to the case or used at a distance of 20 feet or so from it by means of an extension cord.
RADIO & TELEVISION NEWS
Circuits
Pe
“7? ro
Fig. Vai seq
Ordina this pu tion is conduc and m cell cz minati tubing.
The turnin; the lir pointir of lig! steady tron a off the blue g! the re ment ¢ very lk voltage fect or
Fig. except output the ce dark. | for loc tional ] 1-watt the tul pulls i to opel the car
Fig. turn 0 to tur! cell lo
Januar
Ri Si OOK v2w. S.P.S.T.,
PHOTOCELL SK
u7 VAC.
ry
U7 V.A.C.C=—
5K,0.P.0.7. | PLATE
SuTVAC, O-
‘ ciRCUIT RELAY
----4
cL-2
RS 5 MEG.
RE SMEG.
RL3
LL
RB om (SEE TEXT) = v.0.C.
(D)
R:—100,000 ohm, '/2 w. res.
Ro = SRI 5.6K 20MA, tw. +
sila. B 1OK, IMA. RL4 RELAY
sol
@N7VAC
(E) R:—10 megohm pot
(c)
Rs—1000 ohm, 1 w, res.
Ri—1 megohm, 1 w. res.
Rs, Re—S megohm pot
R7—180,000 ohm, 1/2 w. res.
Re—10,000 ohm, 1 w. res
Re—5600 ohm, I w. res.
Cr—400 putd. ceramic capacitor
Cz—S ufd., 150 v. elec. capacitor
Cs, Cy—See text
RL:—S.p.d.t., 5000 ohm plate circuit (Potter & Brumfield LBS or equiv.)
RLe—D.>p.d.t., 5000 ohm plate circuit relay (Potter & Brumfield LM11 or equiv.)
RL:—S.p.d.t., 10,000 ohm plate circuit relay (Potter & Brumfield LSS or equiv.)
RLs—10,000 ohm, 1 ma. relay (Potter & Brum- field SSSD or equiv.)
S1r—S.p.s.t. toggle switch
SOr—A.c. receptacle equiy.)
SRr—20 ma. selenium rectifier
CL-2—Crystal photocell (Clairex Type CL-2)
Vir—5823 tube
Ve—6C4 or 12AT7 tube (see text)
relay
(Amphenol 61-F or
Fig. 1. Five practical circuits using the Clairex CL-2 crystal photocell. Variation of basic circuit in which power is furnished to the output receptacle when light falls on cell. (C) Circuit for operating lighting
sequences.
Ordinary lamp cord is adequate for this purpose, provided that its insula- tion is good, as leakage between the conductors will reduce the sensitivity and may cause erratic operation. The cell can be shielded from stray illu- mination by a short length of cambric tubing.
The unit is put into operation by turning switch S; to “on,” plugging the line cord into an a.c. outlet, and pointing the photocell toward a source of light. R. is adjusted'so that a steady blue glow appears in the thyra- tron and the relay pulls in. Cutting off the light to the cell will cause the blue glow in the tube to disappear and the relay will drop out. The adjust- ment of R, is not critical, except with very low levels of illumination. Line voltage variations will have little ef- fect on the operation of the unit.
Fig. 1B is similar to the basic unit except that power is furnished to the output receptacle when light falls on the cell, instead of when the cell is dark. The switch must be set to “on” for locking operation. The only addi- tional part required is R,, a 1-megohm, 1-watt resistor which is wired to hold the tube in conduction when the relay pulls in. This circuit might be used to open a gate or garage door when the car’s headlights illuminate the cell.
Fig. 1C is a good circuit to use to turn on signs or lights at dusk, and to turn them off again at dawn. The cell load resistor is divided into two
January, 1957
parts, and an additional set of relay contacts is used to change the value of the load when the relay drops out. This modification of the circuit is de- sirable to insure positive operation of the relay at the time of day when the light is slowly fading down to the op- erating value. R; must be adjusted first so that the relay pulls in, turning off the artificial light at the desired amount of daylight, and then R, is ad- justed to turn on the light at dusk. The photocell must be shielded from the artificial light, or the light will blink on and off in a form of oscilla- tion.
(A) Basic circuit which will operate at 1/10th footcandle. (B)
(D) Circuit for high speed operation at low illumination levels, and (E) A simple setup to be used as “intrusion” alarm.
The circuit shown in Fig. 1D is use- ful when high speed operation is re- quired at very low illumination levels. The value of cathode capacitor, C,, depends upon the amount of light available. For .1 footcandle, C, should be 100 wfd. and for 1 footcandle, 10 uid. is adequate. 150-volt capacitors should be used. If fast recovery from an overload of light is necessary, R; must be shunted by capacitor C;, its value being determined experimental- ly, under actual operating conditions. The relay pulls in when the cell is ex- posed to light and drops out when the
(Continued on page 102)
Over-all view of the photocell unit. It is built into a 2” x 3”x5” case. The
placement of parts is non-critical as there is no heating.
CL-2 unit is at right.
of the device is desirable, or where space is limited. The crystal is so
cell relay is usually operated continu- ously, no a.c. “on-off” switch is in-
By HAROLD BERNSTEIN
used at a distance of 20 feet or so from it by means of an extension cord.
RADIO & TELEVISION NEWS
Fig. 1. This sweep circuit module board is used in some Emerson 120306 TV chassis.
Are modules to be repaired or replaced? Will their use
change service techniques?
cuitry well on their way—at least
two manufacturers have released sets using modules as of this writing— it is to the advantage of the service technician to become familiar with the practical aspects of this type of cir- cuit. Although the use of modules in home receiver equipment is new, enough information is available con- cerning these units to enable consid- eration of their replacement and re- pair.
Most service technicians have al- ready been exposed to and have ac- quired some experience in the servic- ing of TV and radio receivers using etched (printed) circuit wiring. Gen- erally, the use of etched wiring has simplified certain phases of servicing, since many ccmponents can be re- placed without having to remove the chassis from the cabinet. Circuits using etched wired boards with con- ventional components usually occupy the same area, if not more, than a con- ventionally wired chassis using point- to-point wiring. This is primarily due to the fact that components must be placed adjacent to one another and cannot be stacked, as was usually done prior to the use of etched circuit boards. Also, etched wiring paths can- not cross one another unless an elec- trical connection is to be made.
One way to reduce the size of a given etched circuit board would be to cut it in several sections and place one section on top of the other with the
Wes receivers using modular cir-
necessary connecting wires and spac- ers added. A module, as shown in Fig. 1, in effect does just this and, there- fore, the use of modules will permit more compact design of both radio and TV receivers. Fig. 2 shows an ex- ploded isometric view of two of the decks of a module used in conjunction with a 6CG7 horizontal control and oscillator tube. With the exception of the horizontal frequency and phase coils, all other components associated with this circuit are contained in this one module.
Construction of a Module
Modules can contain a tube socket plus a wide assortment of components. Furthermore, a module usually con- tains only those components associated with a particular circuit. It is this de- sign factor which will make servicing of modular receivers simple, in many respects, as compared to conventional or etched wired receivers. An excep- tion to this would be the use of a mul- ti-section tube where each tube sec- tion has a different circuit application. The module associated with this type of tube would, therefore, contain com- ponents in more than one circuit.
Modules will also be made without a tube socket and can also contain components which are only a part of a given circuit. An example of such an application would be a module con- taining only those components in the grid circuit of a horizontal output tube. The screen-dropping resistor,
the horizontal-output transformer, the horizontal-output tube, etc., would be wired conventionally.
A module contains a series of stacked ceramic wafers approximately %" square. Various connector patterns are applied to the wafers where need- ed and terminate in a particular wafer notch. Specially designed components are then fastened or printed in place, depending upon the size and type of the component.
When all of the components are in place, the wafers are stacked in their proper order and the 12 riser wires are added. These riser wires not only serve as mechanical supports, but as electrical connectors as well. Each component will be connected between two or more riser wires; that is,-no junction will be made between compo- nents unless this junction is also con- nected to some riser wire as well. This factor is important, as will be shown later, and greatly simplifies the repair of modules. After all of the wafers and risers are fastened in place, the complete unit is coated with an opaque resin and baked. All of these construc- tion steps are performed by automatic machines, which also electrically test the module. Each ceramic wafer con- tains a locating notch between riser wires 12 and 1.
The etched circuit boards will prob- ably also have some form of locating point, such as an etched dot or a small hole. In the event the locating notch is not clearly visible on the deck closest to the etched board, examine the other decks since some of the opaque resin coating may have par- tially filled up one or more of the lo- cating notches. Looking at the dip soldered side of the etched board (top of tube socket, if used), risers are counted in a counter-clockwise direc-
RADIO & TELEVISION NEWS
Vw Vee ee |S SS See vv ose & sow
cell load resistor is divided into two
PS Ss
January, 1957 59
tion starting just to the right of the locating notch.
Approximately 13 modules could make up a complete TV receiver. The tuner and the low- and high-voltage power supplies would be wired conven- tionally. Emerson Radio & Phono- graph Corporation has developed a completely modularized TV _ receiver but presently plans releasing it (Chassis 120306) using only one modular etched circuit board. This board (shown in Fig. 1), using four modules, will con- tain the vertical and horizontal oscil- lator and sweep circuits as well as the syne phase-inverter circuit. Two of these modules contain a tube socket as well. This chassis (120306) will also be manufactured by Hmerson using an etched wired sweep board containing conventional individual | component parts. Both boards can be used inter- changeably and will, therefore, permit accurate comparisons as to cost, pro- duction ease, serviceability, etc.
Troubleshooting and Repair
As already pointed out, an individual module will usually contain those com- ponents which are part of a specific circuit. The methods used by service technicians to isolate the receiver de- fect to a given tube or tubes could readily be extended to include the module or modules. The procedure to use which is not too different, at the outset, from conventional techniques, would be as follows:
1. By eye and ear, check picture and sound to determine which stage or stages might be causing difficulty. A good knowledge of the receiver’s signal path (block diagram) will help.
2. Replace the suspected tube or tubes.
3. If trouble is not due to a faulty tube, quickly check the low-voltage power supply or any other suspected conventionally wired section by means of a voltmeter. If trouble still persists, replace the suspected module. These will usually be located near, if not actually house, the suspected tubes. If more than one module is suspected, it would be a good idea to marrow the trouble down to one module by volt- meter, scope, signal injection, etc.
In all probability, manufacturers using modules in their TV sets will ex- tend their tube troubleshooting charts to include modules. This should great- ly reduce the amount of labor usually connected with the more complicated shop repairs. You will undoubtedly re- call examples of repairs which took many hours of your time only to end up with the replacement of an inex- pensive resistor or capacitor. Trying to account for this labor on your cus- tomer’s repair bill is also a problem since most people are not familiar with the difficulty of certain types of repairs.
The use of modules should, in the long run, materially reduce the aver- age repair time per set. This should permit an increase in work output which, together with the higher list price of a module (as compared to a
January, 1957
single component), should result in more equitable servicing profits. Also, due to the higher list price of a module, the total repair charges to the customer, in general, will not appear to be so overweighted by labor charges, misleading as that appearance can be.
Replacing a TV Module
Generally speaking, components used in TV receivers are larger than those used in radios with the exception of if. coils and transformers, which are approximately the same size. When a tube socket is a part of the module or when a large component is mounted to the deck closest to the etched board, it is necessary for the etched wiring board to have a square cut-out to per- mit the tube socket or component to fit through and allow the module to be flush with the top of the etched circuit board. Where a socket or large component is not a part of the bottom deck (A), individual holes may be used for each riser rather than a large square cut-out. This type of mount- ing method will be found mostly in radios, and the removal of same will be described later.
Where a square cut-out is used on an etched board, it is necessary to bend each of the riser wires over to make contact with the etched wiring. This is usually accomplished by a spe- cial tool which bends ajl of the riser wires at the same time. The complete
etched wiring board is then dipped in .
a solder pot where all connections are soldered simultaneously. To remove such a module for replacement pur- poses, the following procedure is rec- ommended :
1. Insert the small sharp tip of a low-wattage soldering iron (approxi mately 35 watts) under a riser wire and pry riser upward as solder melts. Repeat for all riser wires of module to be removed.
2. Make sure all the riser wires are bent so as to fall within the etched wiring board cut-out.
3. Note the position of the locating notch in the module wafers with re- spect to the etched board before re- moving the module from the board.
Fig. 2. Exploded view of two adjacent decks shows construction detail of mod- ule. Risers are joined in actual use.
SOLDERING IRON
TUBE SOCKET
DECK A
RISER WIRES
LOCATING NOTCH
Fig. 3. Specially designed soldering tip for unsoldering all twelve risers of the modular unit ct the same time.
(This is usually next to some type of locating mark on the etched circuit board.)
4. Replace new module in _ board, making certain the module locating notch is in the proper position.
5. Bend risers over etched wiring and individually solder each riser by means of a low-wattage iron. Make certain all solder splashes are removed to prevent possibility of short.
If reasonable care is exercised in re- moving the suspected module, no dam- age should result. In the event, there- fore, that the replacement module does not repair the trouble, the riser wires of the original could be straightened out and the module used over again as a replacement.
Radio Module Technique
Since a radio has few stages and components as compared to a TV re- ceiver, the use of modules will not ap- preciably simplify radio service as in the case of TV. You will probably find that two small modules can replace all of the individual components in a ra- dio receiver with the exception of con- trols, electrolytics, filter resistor, large coils, and transformers. Since it is not practical to use a separate module for each circuit in a radio receiver, you will generally find that all resistors and capacitors which are a part of the r.f. and i. stages of the radio will be in one module, while all components (except those just mentioned) in the audio circuit of the receiver will prob- ably be part of another module.
Since the majority of radio failures are due to tubes and components which are not included in modules (electrolytics, tubes, oscillator coils, volume controls, etc.), the type of serv- ice will generally be the same as for a conventional radio.
If the trouble is traced to a compo- nent in one of the modules and it is decided to replace the complete mod- ule, the following procedure should be followed:
1. Remove defective module by dip-
61
: 2.2: #0 4 F €@€2 828 NOTE: DECKS 8,08 F OMITTED-NOT USED IN THIS MODULE
Fig. 4. A wiring schematic is most use- ful for troubleshooting. Other render- ings of the module are in Figs. 5 and 6.
Cif /.047yte. w
3 — L047 ute.
calf 3
----------4--7
a t
Fig. 5. Schematic diagram of the tube and modular stage rendered in other ways in Figs. 4 and 6. Numbers in cir- cles refer to riser wires to which the in- dicated points connect. Where a riser number is shown in a square, it indi- cates that the riser has been clipped at some point inside the module itself, and the point indicated is therefore not avail- able for testing at the dip-soldered side of the set's etched-circuit board.
ping underside in a small solder pot or apply a solder iron with a hollow square-shaped tip (this type of tip, shown in Fig. 3, will probably be made available soon) to all of the risers at the same time.
2. While the heat is being applied to all of the risers by one of the above methods, pull the defective module away from the etched circuit board.
(Note the location of the module-posi- tioning notch with respect to the etched board. This is usually next to some type of locating mark on the etched circuit board.)
3. Place a new module in the etched board, making certain to position it as the original, and individually solder each riser in place. A low-wattage iron should be used for this purpose to prevent the possibility of damage to the etched wiring.
Repairing Modules
As already pointed out, the use of modules will speed up certain types of receiver repairs, especially if trouble exists in a feedback circuit (horizontal a.f.c.) or is of an intermittent nature. By replacing the complete module in a given circuit, all components in that circuit are changed at the same time. There will be times, however, when the exact replacement module is not immediately available, and it might be more advisable actually to repair the module.
During the process of troubleshoot- ing the receiver, you might also trace the source of difficulty to a single com- ponent just as easily as to a specific module. With this condition, it would be more economical to repair the module.
The first step in repairing a defec- tive module is to determine which com- ponent in the module requires replace- ment. This can usually be accom- plished by standard service procedures. The easiest components to check are those which would materially change a voltage, resistance, or waveshape reading at a tube pin if defective. Open plate supply resistors, shorted bypass capacitors, open shunt video peaking coils, open coupling capacitors, etc., are good examples of easy-to-lo- cate components.
To check a capacitor which has other components shunted across it presents a more difficult problem. Either a spe- cial type of capacity checker which can check capacitors in the circuit must be used or one side of the capac- itor must be temporarily disconnected from the circuit. To do this in a module, however, is more difficult than in a conventional chassis and would require the cutting of one or more risers. If the capacitor checks good, the cut risers would have to be re- paired, and another component
Fig. 6. Deck-by-
2+ 0) ‘1
deck construction details of the hor- izontal-oscillator and a.fi.c. module, also shown in
Figs. 4 and 5. This type of diagram cannot be used as
readily for serv- icing as the one shown in Fig. 4, but may be useful in drawing up the
equivalent of the
Fig. 4 schematic.
checked. Since this: type of repair is very time-consuming, it should only be attempted in the event that a replace- ment module is not available.
After the defective component is iso- lated by voltage, resistance, or wave- shape measurements at tube pins, you will then have to physically locate the module and the exact wafer to which the component in question is connect- ed. The schematic diagram will indi- cate the module and risers to which the component is connected but will not show the ceramic wafer (deck A, B, etc.) to which the component is at- tached. Before proceeding with the re- pair, it is necessary to know how many other components are connected to the same risers. This is easily accom- plished by referring to a module draw- ing, as shown in Fig. 4.
In the event such a diagram is not available, one can be prepared if a drawing, such as the one shown in Fig. 6, is provided. Fig. 4 is much easier to work with since it clearly shows the easiest method of repairing a module. When converting Fig. 6 to Fig. 4, it will also be necessary physi- cally to look at the module and indi- cate in Fig. 4 the exact position of all cut risers.
Fig. 5 is a conventional schematic of the circuit built into the module. It is not as useful in troubleshooting as the wiring schematic, Fig. 4.
Before going into the actual repair procedure, we should like ‘to point out several facts about the module dia- gram shown in Fig. 4. The arrows in- dicate the points at which the module is wired into the etched board. The components are shown attached not only to their proper risers, but to the proper ceramic wafer (deck). Note that no components are on decks B, D, or F. Components that may appear to be located on these in Fig. 4 are ac- tually on the topsides of the decks be- low or on the undersides of the decks above. Not all of the risers are elec- trically used and some of them are used between only a few of the ceram- ic decks. It is generally easier to re- pair a component which is located on the wafer farthest from the etched board. The most difficult ones are gen- erally located on the wafer closest to the etched board (deck A).
If a circuit analysis indicates that R, is open, the module could be re- paired simply by soldering a new re- sistor between risers 3 and 7. This is most conveniently done on the dip- soldered side of the etched board. If R, were shorted, however, it would first be necessary to remove it from the circuit. Before doing this, Fig. 4 should be carefully studied to deter- mine if such a repair is practical and, if so, the simplest way to handle it. If riser 3 were cut between decks C and E, it would also remove R, from the circuit. If it were cut between decks A and C, it would remove C:, C,, and R, from the circuit as well. If riser 7 were cut between decks C and E, it would eliminate only R2 The
(Continued on page 162)
RADIO & TELEVISION NEWS
tea aan ten =. a |
Atomichron— World’s Most Accurate Clock
HE ATOMICHRON, a multi-pur-
pose frequency producing instru-
ment, was unveiled recently by Na- tional Co., Inc., of Malden, Mass. The most accurate clock in the world, the Atomichron is the first atomic beam clock available for commercial use. By maintaining synchronism with the natural resonant frequency of the cesi- um atom, the device is the most accu- rate primary frequency standard in the world, it was said.
The extreme stability will permit: increased speed and volume of long distance telephone communications in higher frequencies of the spectrum; greater volume of industrial communi- cations; extension of power and pipe line control systems; and increased accuracy in electronic navigational equipment. In the high frequency spec- trum, the Atomichron will permit the use of radio receivers and transmitting equipment of unprecedented narrow bandwidths and precise frequency con- trol, eliminating crowded air waves often resulting in one station or chan- nel interfering with another. In the area of navigation, the device is being used by the Air Force in its experi- mental long-range ‘“Navarho” naviga- tion system.
How It Works
Electrons, and most sub-atomic par- ticles, act in many respects like tiny bar magnets. The outer electron in an atom, like cesium, finds itself in the magnetic field of the nuclear magnet and tends to align itself just like a compass needle. If the electron is disturbed, it will vibrate about its position like the needle. Frequency of the vibration of the analogous com- pass needle is determined by the mag- net strength of the needle, the field in which it is located, its weight, and shape. Corresponding quantities for the electron are fixed, unchanging, and identical for all electrons and cesium nuclei. It is the quality of not chang- ing which makes the vibration fre- quency a primary standard and the Atomichron constantly corrects an auxiliary vacuum-tube oscillator to operate at the frequency of this elec- tron resonance. (See diagram at right.)
A reservoir of cesium atoms is placed at one end of a long, evacuated chamber. As heat is applied, individual cesium atoms drift away from the pool. In the diagram, two’ cesium atoms of different orientations of nu- cleus and electron are considered to be given off and to begin drifting through the atomic beam tube, where they come under the influence of two permanent magnets and an rf. field. The orientation of nucleus and elec-
January, 1957
tron in atom #2 is such that it is attracted to the strong pole of the first magnet, and deflected away from the r.f. chamber. Atom #1 exists in an energy state which causes it to be deflected away from the magnet and toward the r.f. chamber.
When the r.f. field is near the cesi- um resonance frequency, atom #1 will probably emit a photon and change its energy state to the configuration of atom #2. If the r.f. field is not near
Dr. J. R. Zacharias (left), a key figure in develop- ment of the Atomichron, H. C. Guterman (center), and J. H. Quick (right). chairman and president of National Company, view the atomic beam tube.
Front view of the Atomichron, which stands 7 feet high and weighs about 500 pounds. Unit costs $50,000.
First practical atomic primary
frequency standard with stability
better than 0.5 second in 300 years.
cesium resonance, the atom will prob- ably remain at its original energy level.
As the atom passes through the second magnetic field, and if its energy state is unchanged, it is deflected away from the strong pole of the second magnet. If it has changed its energy state in the rf. field, it is deflected toward the strong pole. In this case, however, deflection toward the strong
(Continued on page 120)
OUTPUT CURVE
SIGNAL [STRENGTH
Functional block
R.F_ INTRODUCED IN CHAMBER
diagram of Atom- ichron showing the method of connecting the atomic beam tube
OuTPUT —100pw.
9,192,631,630 + 1IOCPS+ 100CPS-FM
ELECTRON MULTIPLIER OUTPUT
into the system. The output curve shown here rep- resents a device with a “Q” of al-
5 MEGACYCLE CRYSTAL OSCILLATOR
most 50 million.
ATOR fe: SYNTHESIZER
AUTOMATIC FREQUENCY CONTROL SYSTEM
woces- 100mc. 2,o- TION
MooUL A oscu.cator F*iooces-Fm
wf. . ; eo ‘ ip hed 4 teh A. eo ee 22 pte
ih Fidelity
< (aes
Part 9. Output stage characteristics — including power requirements and loudspeaker matching.
Tor parts of this series dealing
with speakers could justly be
deemed controversial. There are several ways of designing near-perfect speakers and there are several ways of judging them. The “end product” is called high fidelity, and whether this results in realism must be a matter of opinion. As no speaker is perfect, the type of distortion present may be ac- ceptable to one listener but not to an- other, and the musical taste of the de- signer himself will literally color the reproduction. As your editor pointed out in a note, there are several schools of thought in speaker design, simply because positive and precise measure- ment of the sound of music is not pos- sible. Moreover, however conscien- tiously I strove to give an impartial account of the important features of speaker design, I suppose it was in- evitable that I should feel that my way was the best way, otherwise I wouldn’t have done it that way!
When it comes to considering the power required to drive the speaker there can be (or, perhaps, should be) no argument at all. There should be no conflicting schools of thought. Our requirements can be stated precisely— there must be no distortion in the am- plifier output within audible limits, and this can be achieved at reasonable cost. Further, the amplifier perform- ance can be measured with precision, so an absolute and objective standard of performance can not only be postu- lated but achieved and proved. In addi- tion, I, as a writer, have no financial or business interests in any amplifier extant or projected. All I want is un- distorted power for the speakers of
64
my choice, and I assume that that is what you want too.
I had hoped to give the answer in a single article, and when I wrote this part and read it through I had to tear it up because it did not answer the basic question—what is the best out- put stage? As a result of much expe- rience I know what I prefer, but when I recalled that in this presumably ex- act field of amplifier design there is a strong body of opinion in favor of tri- ode output stages and another equally insistent on tetrodes or pentodes,
EpITor’s NoTE: The author of this article advocates fairly limited output powers. Don’t miss the article in this issue by David Hafler, who gives the reasons for the use of higher audio output powers.
something more was needed than just another resumé of the various types of output stages. And the high-fidelity enthusiast must have heard of or tried dozens of different circuits, each of which was supposed to be the last word in perfection. Writing an article on an amplifier is the easiest form of technical journalism; the demand is insatiable, for everybody wants some- thing better, and most amateurs can build an amplifier if they can’t build a speaker.
This is my thirtieth year in speaker design. All that time I have wanted better and still better amplifiers; being something of a specialist I have gone through the process, year after year, of hooking up every circuit that has come along, in the belief that others knew more about it than I did. I don’t know any more about amplifiers than others, but I have found out where
most of these didn’t match up to my requirements, and it is that knowledge I shall try to give you. This article, therefore, will deal with the approach to the problem; the next will con- structively criticize the various types of hi-fi output stages so that you can make your own selection.
How Much Output Power?
Any exhibitor at an audio fair knows quite well that if he stages a demon- stration with artistic restraint, with a genuine desire to display his. equip- ment as it should be heard in a civilized home, he will lose business. It isn’t a case of one exhibitor trying to shout the next man down; it is what draws the crowds that matters. Every show has a large proportion of acoustic rubbernecks, wise guys who don’t know much about music, but reckon they know a lot about hi-fi. They dash from one room to another, listen for a minute and off to the next, rather like the traditional Yankee doing a three-day tour of Europe. If nothing very much seems to be hap- pening in room A and room B is rais- ing hell, then the crowd will be in room B, whatever the real quality of reproduction. In due course these peo- ple will report to their friends that the company in room A doesn’t know how to put on a show. A manufac- turer hires a room at an audio show for the sole purpose of selling his equipment, and whether he likes the noise he creates in that room or not, his main interest is the order book. If he gets the orders, he is doing the right thing; if he doesn’t, he isn’t. And that seems to be all there is to it.
But there is more to it, for this un- fortunate state of affairs has precon- ditioned the audio fan into assuming that hi-fi and hi-volume go hand-in- hand, and that is not only bad for your
RADIO & TELEVISION NEWS
neighbor but bad for yourself. If you have never been to a first-class sym- phony concert, I suggest you go to one. You will get the shock of your life, for the first thing that will strike you is the fragility (the only word I think fits the case) of the orchestra. I am assuming you normally run your equipment at a fairly high “realistic” volume, and what you will find is the conductor working quite hard, egging on the instrumentalists to do some- thing grand, and all that comes out is a thin strain of music which, if it is a Mozart or Haydn program, may be so quiet that any noise from the audience will ruin the whole thing. If, however, it is the Dies Irae from Berlioz’s Requiem, with full orchestra, 16 tym- pani, 4 brass bands and a choir of 300, then it doesn’t matter very much what. the audience does; it will be something like Haydn being played at an audio fair. The great “trick’’ rec- ord of the 1952 New York Fair was the fine Westminster recording of the Haydn “Military” Symphony (No. 100). Haydn composed far finer sym- phonies, but could I demonstrate these? No! Over and over again I was asked to put on “The Military and give it all you have. I want to hear that big bass drum.” And I had to do it or out they went! Music is more than big bass drums, and that was no way to demonstrate realistic sound re- production.
If you are a regular concertgoer you are accustomed to the refinement of good music beautifully played and con- ducted. If you can get the same pleas- ure from a record of a work you love as you got in the concert hall, you have a good reproducer, and the vol- ume will be adjusted to suit.
The amount of power required to produce that volume depends on the size of the room, the way it is fur- nished, and the sensitivity of the speaker. As I have explained in an earlier article, a horn-loaded speaker is more efficient than a direct radiator, and the sound output of the latter de- pends on whether it is enclosed in a housing which projects the sound from the back of the diaphragm or absorbs it. Order of sensitivity is, therefore, horn-loaded, direct radiator in acoustic phase-inverter, direct radiator in in- finite baffle or closed box. For these three types of speaker systems the out- put power required for an average living room of about 2500 cubic feet is about 3, 6, and 11 watts undistorted peak. As the smallest high-fidelity am- plifier generally available is a 10-watt job, and others are available with claimed undistorted outputs up to 60 watts, there seems to be something wrong with my figures. Which brings us to the situation that there is more in assembling a hi-fi system than buy- ing an amplifier whose looks and price appeal to you and using it to drive the speaker of your choice.
The apparently simple process of connecting a speaker to an output stage by means of an audio trans- former is, in reality, an extremely
January, 1957
complicated business indeed. The prob- lem is usually avoided by adopting what might be called technical clichés. Given the optimum load of the output stage, as revealed in the tube cata- logues, and the nominal impedance of the speaker, the ratio of primary to secondary turns in the output trans- former is obtained from the formula: . _«|/Optimum load of output stage _— \ Speaker impedance It is common knowledge that a re- serve of power will guard against dis- tortion through overload on peaks, and if the amplifier tends to distort, either through poor design or because of the critical load of tetrodes and pentodes, put in some negative feedback which will reduce distortion and lower the plate impedance of the output stage. It seems so easy. Now let us consider what really does happen.
Output Transformer Characteristics
To conform to the foregoing ratio formula it is obvious that the trans- formation ratio must be constant for all frequencies if the load (i.e., the speaker) has constant impedance. A transformer is an impedance matching device, and the load reflected onto the output tubes is that of the impedance of the secondary circuit multiplied by the turns ratio squared. This is with an ideal transformer, but practical transformers are not ideal. At low frequencies the ratio is less by a fac- tor:-which includes the plate resistance of the output tubes, the resistance, and inductance of the primary winding. At high frequencies loss of ratio results from leakage inductance (through im- perfect coupling between the two windings), self-capacity of the wind- ings (acting as a short circuit at high frequencies). To make things more difficult, the transformer will peak at a high frequency through resonance of a low-“Q” circuit formed by the pri- mary reactance and resistance and the self-capacity of the windings; beyond this peak the response falls rapidly.
The design of audio transformers is a perfectly straightforward matter for a competent technician, but is too com- plex to be included in this series. The
Fig. 35. 70 cps.
Fig. 34. Hookup for impedance measure- ment of loudspeaker. See text for details.
reader will probably buy his output transformer from a specialist manu- facturer, but the best results will not be obtained by using a so-called uni- versal transformer. As you can see, even a well designed transformer will not have a constant transformation ratio unless the actual output tubes are specified as well as the speaker impedance. A tapped secondary may not have equal coupling for all fre- quencies, and although the primary inductance may be adequate to give good bass, the actual value of the pri- mary inductance depends not only on the lowest frequency to be reproduced, but the relationship between the op- timum load and the a.c. resistance of the output tubes. Different tubes may have the same load resistance yet dif- fer in their plate resistance. This, in turn, determines the damping factor and accounts for the triode-pentode controversy. The a.c. resistance of tri- odes is about a quarter of the optimum load; tetrodes and pentodes have an a.c. resistance about five times the load resistance. A good deal of the prejudice against the latter is due to the fact that they are not properly used.
Loudspeaker Characteristics
Apart from the acoustic perform- ance of a speaker, it has two proper- ties which are directly associated with the output stage—power-handling ca- pacity and impedance. Advertisements and catalogues frequently state that some particular model is, say, a 15- watt speaker, but this bald statement means nothing beyond an implication that it is suitable for use with a 15- watt amplifier. It may not be.
As far as frequency is concerned,
Impedance curve of a typical 4 ohm loudspeaker with a bass resonance at Eight and 16 ohm speakers would have proportionate variations of impedance.
L
IMPE DANCE-OHMS
IKC. FREQUENCY-CPS
the power-handling capacity of a speaker depends on the flux density in the gap, the freedom of suspension and the size of the cone. Fig. 13 (Part 4) gives some information on this; it indicates that for speakers of 5% effi- ciency with a free movement of cone and coil of % inch (a fairly usual state of affairs) a 5-watt input produces maximum deflection at 30 cps in a 15- inch speaker; at 45 cps in a 10-inch speaker; and at 80 cps in a 5-inch speaker. Any greater power can only result in gross distortion and mechan- ical damage. It follows that the appli- cation of any power greater than 5 watts is restricted to those frequen- cies higher than those just listed at which the cone movement does not ex- ceed % inch. In any case the lower limit of non-distorted reproduction is the bass resonant frequency, for below that the output is mainly third har- monic. A speaker has, therefore, vir- tually no power-handling capacity be- low bass resonant frequency, and above that is limited by the cone size— free movement factor. (Certain types of enclosures can modify the bass re- sponse, as described previously in this series, but acoustic output of a speak- er and its enclosure should not be con- fused with the fundamental power- handling capacity of the speaker itself.)
At higher frequencies, where cone movement is of no consequence, the limiting factor is dissipation of heat generated in the voice coil. If watts go into the coil, the inductive compo- nent is wattless, but the resistive com- ponent must create heat, and if the temperature rise is too great the coil as- sembly will be destroyed. Some read- ers may have had the unhappy expe- rience of burning out a speaker when no signal was fed into the amplifier, simply because there was enough su- personic oscillation in the output stage to do the damage. It has happened to me. At middle and high frequencies, therefore, the power-handling capacity of the speaker is a function of the ac- tual size of the voice coil and the heat radiating abilities of the adjacent metal parts.
Finally is the question—what is the
impedance of the speaker? It is not the figure quoted by the manufac- turer, for it varies widely with fre- quency. Quoted speaker impedances follow on from an old rule-of-thumb concept that the impedance of a speak- er is approximately twice the d.c. re- sistance of the voice coil. For design purposes in cheap equipment this is near enough not to matter, but it is not near enough for the best results. The speaker manufacturers quote as usual impedances 4, 8, and 16 ohms, and the output transformer manufac- turers obligingly tap their secondaries at these figures.
There are dozens of versions of the so-called “equivalent loudspeaker cir- cuit,” which consist of more or less complicated networks of resistance, inductance, and capacitance; the varia- tions derive from different opinions of how the various parts of a speaker's construction and behavior shall be in- terpreted in terms of inductance and capacitance. Pure resistance does not vary with frequency but the inductive and capacitive reactances do, so the impedance of the speaker must vary with frequency. In general, there is a sharp rise in impedance at bass res- onant frequency, then the normally quoted impedance at about 500 to 1000 cps; after this the impedance rises at an increasing rate owing to the in- ductance of the voice coil. How, then, if you cannot get a guaranteed imped- ance curve from the maker of your speaker, can you determine its imped- ance? The simple answer is to meas- ure it, and this is almost obligatory in the case of multi-channel systems with dividing networks, for a very compli- cated total network is involved.
Fig. 34 shows the output transform- er of an amplifier which is fed from an audio oscillator. Across the sec- ondary a known resistance R and the speaker under test are connected in series. An a.c. peak voltmeter can be connected across either R or the speaker. R must be either a noninduc- tive wirewound resistor or a bank of composition resistors of a wattage as high as the audio power from the am- plifier. If R were not used, the speak-
Fig. 36. The ideal curve of a multi-stage amplifier to give a level response from 50 to 15,000 cps with 30 db of negative feedback and a safety margin of 10 db (to guard against instability following heavy transients) is shown by the solid line below. The dashed line shows the response of a well designed amplifier with- out step circuits. The step circuits for the desired bass and treble attenuation are shown below their respective portions of the frequency spectrum. These are seen to consist of the networks designated “R” and “C” in the pentode amplifiers.
i
lll
FREQUENCY-CPS
er might be burned out with steady high inputs. Signals of various fre- quencies are injected into the amplifier and readings at each frequency taken across R and then across the speaker. Call the voltages across these He and Es respectively, then:
Impedance of speaker = aba Fn R
It is important to take a careful reading exactly on the bass resonant frequency, indicated by a sharp rise in the voltage reading across the speaker. When all the readings are taken, a curve is drawn, which will look like Fig. 35, which is a curve of a typical 4-ohm speaker with a bass resonance at 70 cps.
If the output transformer has been chosen to give the optimum load with a secondary impedance of 4 ohms, then there will be serious mismatching at the bass resonant frequency and in the extreme treble. It has been my expe- rience that, since all frequencies are equally important, such a _ speaker should be considered to have an av- erage impedance of 8 ohms. You will notice that the rise in impedance is much greater in the extreme treble than at the bass resonant frequency. This has an effect on the reproduction when the speaker is coupled up for its nominal impedance.
If you study the figures for triodes and tetrodes or pentodes in the tube manuals, you will see that the latter give more power and less distortion than triodes for a given plate supply, but this is only when the load is rea- sonably correct. The optimum load gives the optimum power without dis- tortion, but if that amount of output power is required and the load is wrong, distortion is excessive. Triodes are not as critical as to optimum load, and unless the amplifier is driven hard, the distortion from this mismatching will not be enough to worry about. As it is seemingly impossible to produce a speaker with constant impedance, a speaker assessed at its nominal imped- ance will give less distortion in the extreme highs with triodes than with pentodes when the amplifier is driven hard; hence the term “pentode qual- ity.” But as you can now see, this is not due to pentodes as pentodes but because the wrong load is applied to them at high frequencies. There are ways of getting over this difficulty, as I shall explain in the next article; for the moment, my suggestion of doubling the nominal impedance will give much better general quality.
Negative Feedback
There is a good deal of misappre- hension as to what negative feedback can do. In later articles the practical application will be discussed in a tech- nical way; for the moment I shall summarize what it can do and what it cannot do in terms of the performance of a typical audio power amplifier.
Negative feedback reduces the gain of an amplifier. The “feedback factor”
(Continued on page 148)
RADIO & TELEVISION NEWS
By DONN G. SHANKLAND
Front panel and internal views of an inexpensive vacuum-tube electrometer.
Electrometer- A Very High Input Resistance V.T.V.M.
Inexpensive, easily built servicing instrument has input resistance of about 100,000 megohms for high Z circuits.
voltage drop across a 10-megohm
resistor? As you know, a multi- meter is a virtual short across such re- sistors on the low voltage ranges, and even a vacuum-tube voltmeter, with its 1l-megohm input resistance, will draw. enough current to change the voltage being measured. How, then, can one measure such voltages as grid bias in a superregenerative detector, automatic volume control voltages, and some screen voltages?
The answer lies in the use of an “electrometer,” a device of extremely high input resistance. Such units -are normally quite expensive, but this ar- ticle will describe such a unit which can be built by anyone familiar with a drill, file, and soldering iron.
The instrument is basically a simple triode amplifier connected as a cath- ode follower, with a conventional volt- meter reading the cathode voltage. See Fig. 1. Such a connection has a very high resistance, as the grid is normal- ly held negative with respect to the cathode by virtue of the cathode-fol- lower action, so the only load the input circuit sees is that due to the grid cur- rent of the tube. Most tubes have a grid current of about .01 ua. although specially designed tubes can be op- erated at even lower grid currents. For this instrument, a 6AK5 was chosen, as its grid current is about 10~“ wa. and the tube is easily available. A better tube would be the 959 acorn tube, but it is more expensive new, and sur-
H ore you ever tried to measure the
January, 1957
plus ones are not always available. Two defects of the circuit shown, how- ever, are that the voltmeter will indi- cate the tube bias even if the grid is at zero voltage, and the voltage read will vary considerably with changing sup- ply voltage and different tubes.
To overcome these defects, a bal- anced circuit is actually used. In this, the voltage difference between the cathodes of two similar tubes is meas- ured. See Fig. 2. With the grid of the left-hand tube grounded, the volt- meter reads zero, as the two cathodes should be at the same potential. When a voltage is applied to the input, the voltmeter reads this as a change in the cathode voltage. An analysis of the circuit shows that the voltage across the cathodes in this case is Eeathoae = 1/(1 + 1/u) Einpu: and so, since » (the amplification factor of the tube) is quite large and does not vary greatly, the voltage indicated is the true volt- age. The small correction for the 1/s term is achieved in this instrument with a calibrating resistor. Also, if the power supply voltage changes, the cathode voltages change together, can- celling a large part of the possible error. The resistor, R., is a zero-set resistor to correct for small differences in tubes and the cathode resistors, Rx.
The construction of the device pro- ceeds in three stages: mechanical, wiring, and calibration. The unit was built in a Bud “Minibox” measuring 3”x 4”x5” with a hole cut to fit the meter used (0-200 wa.). A chassis was
built of copper sheet and the tube sockets were mounted and partiaily wired. A 45-volt battery, RCA VS-055, just fits in the space below the meter and is held with copper clips. The fila- ment transformer and switch were mounted at the top of the case as shown in the photographs.
A porcelain feedthrough insulator was used for the grid connection of V, (Fig. 3). Care must be taken that nothing touches this lead and that the insulator is clean as leakage resistance here could affect the operation of the device. Steatite sockets must be used
(Continued on page 114)
VOLTAGE TO BE MEASURED
+
dig 7
rents
Fig. 1. The basic electrometer circuit.
Fig. 2. Addition of balancing circuit.
VOLTAGE TO
AAU |-——
The completed saw-tooth substitution box
makes a compact unit for the bench.
Substitute vertical or horizontal saw-tooth pulses to deflect TV sets are supplied by junk-box unit.
put out a saw-tooth waveform
with enough amplitude to drive a horizontal amplifier should find its place on the workbench of the busy television technician.
As a general rule, quite a bit of the trouble experienced in television serv- icing originates in the vertical or hori- zontal sweep circuits. If some method of direct substitution similar to that used in checking the oscillator tubes themselves could be employed, it seems this would be the answer. Not only is substitution generally conclu- sive, but it is also time-saving. With a scanning generator, this type of sub- stitution could be accomplished and a large number of tedious tests could be eliminated.
The fact that a generator of this type can be built from parts found around the shop makes it a worth- while project for anyone who wishes to make a quick check of the horizon- tal and vertical oscillator circuits of almost any television set.
The instrument to be described was tried on virtually every known make of television set and it was found that there was sufficient drive to the grid of either vertical or horizontal ampli- fier stages.
The peak-to-peak output voltage of the instrument was of sufficient am- plitude to drive the grids of the ver- tical or horizontal amplifier circuits of the set under test by injecting the saw-tooth signals into the preceding coupling circuits. This approach to the problems of no high voltage or of lack
68
A SCANNING generator that will
or deterioration of vertical sweep will give evidence as to the point at which the trouble may be originating.
How It Works
Primarily, the circuits of both hori- zontal and vertical stages in the in- strument are simple multivibrators of the type found in most television sets. The horizontal oscillator stage, which is a 12AU7, oscillates at a frequency determined by the resistor and capac- itor combinations found in the grid, plate, and cathode circuits of the dual triode.
The horizontal generator is V:, while V. is the vertical saw-tooth output stage. These conventional cathode- coupled multivibrators, as Fig. 1 illus- trates, do show some difference from their cousins in TV sets: there is no provision for a pulsed input *~ either stage to accomplish exact synchroniza- tion.
As will be seen shortly, an advan- tage results from this arrangement. Also, if desired, an optional synchro- nizing input can be added to the cir- cuit, with jacks brought out to the front panel for connection to sync take-off points in the receiver.
With the selector switch in the hori- zontal position, the plate voltage is fed from the “B+” supply to the plate re- sistors of V:. The 15,750-cycle saw- tooth output from C; goes through the switching circuit to the output termi- nals on the front panel. One output terminal, Ji, is at ground potential go- ing through the test lead to the chassis of the set under test. The hot output
aft SAWTOOTH OUTPUT
terminal, Jz, can be connected directly through the test lead to the grid of the horizontal amplifier.
The output may also be fed through the coupling circuits, such as the drive control and other components in this portion of the circuit. By connecting the output of the generator to the output plate of the horizontal oscil- lator tube of the set under test, it is possible to test a large number of these components to see if they will pass the saw-tooth voltage to the grid of the horizontal amplifier.
After the raster has been formed by applying the saw-tooth voltage to the grid of the horizontal amplifier it is now possible to adjust the hold con- trol R;. The picture may be brought into a momentary lock-in position. The picture will not stay completely locked in, but will keep framing due to the lack of horizontal syne voltage from the syne separator and phase de- tector circuits. This is not a disad- vantage, due to the fact the hold con- trol on the scanning generator allows one to free-wheel the picture and view the sync information.
The principle of the vertical multi- vibrator circuit is primarily the same as the circuit of the horizontal oscil- lator stage, the only difference being in the size of the components used to change the operating frequency of the circuit.
Once again the operation procedure is very similar to the horizontal check. This time the vertical position is set on the selector dial and a vertical saw-tooth now exists at the output terminals.
The hot lead from the output ter- minal goes to the grid of the vertical amplifier, or through the coupling net- works, and a raster is formed on the
RADIO & TELEVISION NEWS
television screen.” The vertical hold control of the gererator now controls the circuit and the picture can be locked in near its framing frequency.
The power supply is a conventional full-wave rectifier type and it is highly recommended that the plate voltage to the oscillators be kept quite close to 320 to 340 volts d.c. Any large change may upset the oscillator stages so they will not lock in at the proper frequency.
If desired, either horizontal or ver- tical oscillators of the scanning gen- erator may be locked in so that the picture can be viewed without free wheeling the hold controls. It is pos- sible to feed horizontal syne from the phase detector of the set under test, or feed vertical syne from the inte- grator circuit of the set under test.
Input terminals can be mounted on the front panel to accommodate this type of input. The terminal leads can be run directly to the input grid of V; or Vz.
Since a single saw-tooth source can- not provide output that will meet the exact waveform amplitude and shape requirements for all sets, there will, of course, be deviations in linearity and height or width. However, that should not detract from the usefulness of having a saw-tooth generator avail- able for test substitution.
The chassis layout is not critical and may be arranged to accommodate the parts on hand.
A chassis 5%” x 4%” was used with a 6” x6"x6” cabinet and ample room was found to mount all parts. The cost of building this unit is quite small. Using all new parts, it can be done for less than $20.00. —30-
Bottom view of the scanning generator chassis shows relatively straightforward layout and wiring practice used in assembly.
January, 1957
R:—100,000 ohm pot Rz, Re—100,000 ohm, 12 wm. res. R:—1 megohm, 2 w. res. Ri—1200 ohm, 2 w. res. Ri—4.7 megohm, 2 w. res. Rr—47,000 ohm, 2 w. res. Re—22,000 ohm, 2 w. res. Ro—3900 ohm, 2 &. res. Rw—470,000 ohm, 2 w. res. Rir—2 megohm pot Ru—z2.2 megohm, 2 wm. res. Ris—240,000 ohm, > w. res. Rij— 1000 ohm, 5 w. res. Ci, C-—270 yufd. silver mica or zero tempera ture coefficient capacitor
SAWTOOTH OUTPUT
Co—.033 ufd., 400 v. capacitor
Ci\—.047 yfd., 400 v. capacitor
Cs, Co—.005 yufd., 600 v. capacitor
Cr—.001 pfd., 400 v. capacitor
Cs—.1 pfd., 400 v. capacitor
Co, Cw—30/30 pfd., 450 v. elec. capacitor
S1—S.p.s.t. toggle switch
Se—D.p.dt. wafer switch (CRL #1462 or equity.)
J1, Jo—Banana jack (use one red, one black)
PL:—6.3 volt pilot light (Type #47)
Tr—Power trans. 230-0-230 v. @ 50 ma.; 6.3 v. @ 2.5 amps. (Stancor PC8418 or equiv.)
Vi, Vi—12AU7 tube
Vs—6X4 tube
Fig. 1. Complete schematic diagram and parts list for the substitution saw-tooth scanning generator. One multivibrator, V:. provides a horizontal saw-tooth for re- ceiver checking. Another multivibrator, V:. fulfills a similar role at the vertical rate.
Top view of the generator out of its housing indicates the un- cluttered layout obtained despite the small size of the device.
By BERT WHYTE
on three-channel stereo, I have had many
letters and other communications on the subject. There would seem to be little doubt that there is a great deal of interest in this field. Well, things in the world of three- channel stereo have been going very slowly since my column and I have had nothing to report. However, within the past two weeks a great deal has been popping! To take first things first, Mercury has constantly been adding to its backlog of three-channel stereos, with another 30-odd tapes “in the can” since I first told you of this activity. Work is progressing on dubbing facilities, but nothing concrete yet. You never know how close help is to home, until you need it! Most readers of this column probably know the byline of a Mr. Charles Boegli, whose writ- ings have appeared in the pages of Rapio & TELEVISION News with some frequency. Mr. Boegli was kind enough to contact me about three-channel stereo, and it seems that a company of which he is an officer is about to conclude negotiations with a Japanese firm for the importation of three-channel stereo tape heads. Leave it to our astute Japanese friends! As far as I can learn, these will be offered for sale in this country and will con- form closely to American manufacturing standards. In addition to this startling devel- opment, the Japanese have embarked on a program of three-channel recording and re- portedly have already quite a backlog and facilities for dubbing them. Not long after this news, I learned from another source that still another Japanese outfit was engaged in three-channel stereo recording and they are purported to have over 60 tapes ready for dubbing! What the material is (other than I know it is mostly symphonic) and what it sounds like, I don’t know at this moment, but I am supposed to have a demonstration in a few weeks time. I might add that if present plans jell in time, several of the peo- ple involved in this Japanese deal have stated that they hope to be able to demon- strate the three-channel stereo at the Los Angeles Audio Show. Obviously all this activ- ity can have nothing but a salutary effect on stereo affairs in this country. Let’s hope so, and soon!
THE UNABASHED VIRTUOSO
TIGER ON THE KEYS Stephen Kovacs, pianist. Elektra 106, and Elektra 111 respectively. RIAA eurve. Price $4.98 each.
If you particularly savor piano music in the lighter vein, these two Elektra discs should prove most gratifying. Stephen Ko- vacs is a remarkable talent and in the range of material covered displays virtuosity far beyond its demands. In fact, so good is this fellow that one wonders at his predilection for this lightweight stuff when he is so ob- viously of concert-hall calibre. Well, I guess
70
iy YOU can imagine, ever since my column
that’s Mr. Kovac’s affair, and if he doesn’t mind lavishing his talent on this relatively trivial repertoire, we'll just sit back and en- joy ourselves. With his technical command, his keen humor, and his depth of feeling he makes newly interesting such tired war- horses as “Danse Macabre,” “Humoresque,” “Flight of the Bumble Bee,” “12 St. Rag,” “Sabre Dance,” and others including (s’help me!) the “Beer Barrel Polka.” Sound fanciers of piano won’t de disappointed either as this is one of the most technically satisfactory piano recordings on LP. Quite interesting is the fact that the microphone used was an RCA-M13026A, a bi-directional ribbon type discontinued by RCA back in the 1930's! Whatever shortcomings this mike had, it would certainly seem to be one of the best piano mikes available. The sound seems very wide-range, utterly clean, and with an espe- cially good transient response. Little or no ringing can be heard, and hammer action noise was minimal. Add intelligently spacious acoustics and it all adds up to a superbly realistic piano sound. A pair of fine “show- off” records.
RACHMANINOFF SONATA IN G MINOR FOR CELLO AND PIANO Zara Nelsova, cellist, and Artur Balsam, pianist. London LL1480. RIAA curve. Price $3.98.
This lovely work has been recorded once previously . . . an excellent performance by Schuster and Pennario on a Capitol disc. For those who may have “built-in” prejudices against chamber-style music, let me assure you that if you will listen to this work you will like it. One would have to have a very narrow perception of music to be unmoved by its immediate and ingratiating charm. Performance-wise, Nelsova seems to be more at ease with the score than was Schuster... her technical fluency is beyond reproach, her cello has a gorgeous fat tone, very warm and intimate. Balsam is somewhat reticent in his playing, but is generally satisfactory. Sound- wise this is a superb recording of the close-up variety, but with sufficient room tone to sus- tain liveness. The cello and piano are ultra- clean in their projection and the engineers have managed an exceptional balance be- tween them. This disc has a slight edge in over-all quality as compared to the Capitol version, but both have their virtues and one’s preference is largely a matter of personal taste.
VERDI-MACKERRAS
THE LADY AND THE FOOL WEBER-BERLIOZ
LE SPECTRE DE LA ROSE MINKUS
The opinions expressed in this column are those of the reviewer and do not necessarily reflect the views or opinions of the editors or the publishers of this magazine,
DON QUICHOTTE New Symphony Orchestra conducted by Robert Irving and Anatole Fistoulari. London .LL1518. RIAA curve. Price
This is most obviously a record for the ballet enthusiast. The Minkus and Weber scores were previously issued by London on a 10 inch disc, as was the Verdi-Mackerras suite. The sound, which was excellent in the 10 inch version, seems to have been improved in this new 12 inch coupling. Whether this is new cutting techniques or whatever .. . strings, brass, and woodwind are cleaner, much better definition is notable, and dy- namic range appears extended. Robert Irving and Fistoulari are old and practised hands with ballet scores and do full justice to the material. The Verdi derivation is to me the most interesting, consisting of music taken from 11 of his operas, which except for “Ernani” are relatively obscure. That their obscurity is no doubt deserved detracts in no way from the material excerpted, which for the most part is highly listenable. All in all a most satisfactory recording which should enjoy a brisk sale among balletomanes and more casual listeners as well.
MENDELSSOHN
PIANO CONCERTOS #1 AND #2 Peter Katin, pianist. London Symphony Orchestra conducted by Anthony Collins. Lendon LL1453. RIAA curve. Price $3.98.
This is the third recording to appear in which the two Mendelssohn piano concertos are coupled. Taken as a pair, they have liter- ally no competition either in sound quality or performance. Considered as separate en- tities, Katin is still top man in the 2nd con- certo and more than holds his own in the first concerto, even if he can’t pre-empt Gilels’ superb reading on a Colosseum disc. Splendidly endowed with technical ability, Katin is not yet matured sufficiently to match the refinement of playing exhibited by Gilels. However, when sound quality is also considered this evens the score for Katin as much of the Gilels advantage is lost in the altogether miserable sound of the Soviet tapes. Katin’s playing is full of fire and spirit, but he never oversteps the bounds of good taste by committing any pianistic excesses. His attitude is obviously respectful and as such he makes these oft-played works newly enjoyable. With fine support from Anthony Collins and the men of the London Sym- phony Orch., and with some of London’s best piano recording, this disc is highly rec- ommended, especially to those who have had a surfeit of the Tchaikovsky, Grieg, and Schumann concertos.
DEBUSSY
IBERIA
LA MER
PRELUDE TO THE AFTERNOON OF
A FAUN Detroit Symphony Orchestra conducted by Paul Paray. Mercury MG50101. RIAA curve. Price $3.98.
Lately there has been a regular rash of re- cordings of the “Prelyde to the Afternoon of a Faun”, and it goes without saying that “La Mer” and “Iberia” are hardly new to the LP catalog. But with really great music fa- miliarity cannot breed contempt, and indeed with recordings there is always the hope that the newest will be that elusive phantom, the “definitive” version. This recording presents Paul Paray’s statement on the three greatest Debussy works and it is, I think, as close to “definitive” as we are likely to encounter. Wow! I can already hear the yowls from the Toscanini camp on the matter of “La Mer.” As long time readers of this column know,
Continued on page 144)
RADIO & TELEVISION NEWS
A V.H.F. Field-Stren
KA
4 vA
oth Meter Adapter
By GENE BRIZENDINE, wate
Profitable Products
Details on an inexpensive and compact
unit which can be used with practically
any service-type volt-ohm-milliammeter.
: oe a ; A — 4 Ye .
The adapter in place on the author's Simpson 260 meter and close-up of the adapter unit.
HE field-strength meter adapter to
be described is low in cost, compact,
and wide-range. Since the costliest item in a field-strength meter is usual- ly the sensitive microammeter, it was decided to utilize the low-current movement already available in the av- erage volt-ohm-milliammeter. The pop- ular Simpson 260 meter was used by the author but other makes are equal- ly adaptable.
The circuit is simplicity itself, utiliz- ing a wide-range tank circuit, a semi- conductor diode, and an r.f. bypass capacitor. The extremely wide cover- age of the meter adapter is made pos- sible by the use of a special tuning capacitor which is marketed by Lafay- ette Radio. By using this unit, which measures only 1” x 1” x 5%”, the tuning range is 50 through 300 megacycles.
The adapter is assembled in a 1%” x 1%” x 2%,” hinged plastic box of the type now popular for packaging small items like transistors and fishing lures. First, hold the box above the position it will occupy on the meter. Mark the point for drilling the hole which fits around the “Ohms Zero” knob. After drilling this hole, position the box again and accurately locate and drill the holes for the output pins. Finally, drill a hole for the antenna pin jack.
The output pins are simply two small plated nails, cut to proper length for a snug fit into the meter pin jacks. The pins are passed through soldering lugs and soldered to the lugs. Now solder small, flexible wires to the lugs. Next, with the box in position on the meter, pass the pins through their holes in the box, into the meter pin jacks. Apply the iron to the nail heads and, as the plastic softens, press the lugs into the plastic material. Allow complete cooling before removing from the meter. Seated with a bit of care, the pins are solidly anchored to the box.
The horseshoe tank (a 1%-inch length of No. 14 wire) should be bent
January, 1957
around any round object so that it will fit the capacitor terminals. The tank should be soldered to the tuning ca- pacitor before assembly in the box. The dial scale was first temporarily taped outside the box for calibration purposes. The antenna connection is tapped onto the tank at the mid-point. The usual precautions should be exer- cised in soldering to the diode and other small parts. The antenna is made of a length of %” brass welding rod. Its length, although not critical, may be cut to the shortest length which gives adequate meter readings. For some uses around high-powered transmitters, no antenna may be re- quired.
The dial scale was calibrated using a signal generator as the standard.
Complete schematic diagram and parts list for the v.h.f. field-strength meter unit.
Kis
te ke TEXT) pute. rE
Cr—365 pufd. midget tuning capacitor (Le- fayette MS-274)
Cx—.002 yufd. capacitor (Aerovox Type P83Z or equiv.)
Lr—Tank inductor, 142” of No. 14 wire (see text)
1—I1N56 crystal diode
1—Plastic box (Lafayette MS-156)
The generator output was coupled to the field-strength meter tank, using a one-turn link on the generator lead. Alternatively, any oscillator or trans- mitter of known frequency may also be used as the calibrating standard.
The scale points were transferred to another sheet of paper, using carbon, and final markings were typed in. The finished scale is placed inside the case, for protection. Finally, the case was sealed, using Duco cement sparingly, on the joining surfaces. After the unit is dry, it is very sturdy and service- able.
In use, the adapter is plugged into the meter and placed where the meter deflection is visible during transmitter or antenna adjustments. Possibly its most useful application has been in tuning up mobile, marine, and aircraft transmitters where the lack of space precludes the use of elaborate or bulky instruments.
In addition to antenna system ad- justments, the adapter also serves as an absorption frequency meter and is useful in the tuning of multiplier stages for maximum field output. It will also help to locate leaky shielding and, with headphones clipped to the output pins, modulation quality and carrier hum may be judged.
All in all, this tiny adapter more than pays its way for the small space it occupies in the service technician's kit.
71
Hams from Eimac put up a beam antenna for “Field Day” operations under the call letters W6UF/6. The
antenna is a 20-meter “Bantam” beam mounted on a TV antenna crank-up tower. Its husky “bow-tie” ele- ments and silver-plated loading coils produce a half- size beam offering essentially full-size performance.
. . OY err te 4 ay % 5
oe 6 ‘ geen
-, he pO kaw ae ey a
The advantage of using a shortened rotary beam is often
not fully appreciated by hams. Here is the true story!
EW experienced radio amateurs Pricca to be told the advantages of a
rotary beam antenna, especially for working DX on the frequencies of 7 me. and above. Most of the more suc- cessful amateurs use them on the 14-, 21-, and 28-mc. bands. A smalier per- centage (those with the strongest sig- nals) use them on 7-mc., and a few even use them on the 3.5-mc. band.
Figs. 1A and 1B compare the radia- tion patterns of a %-wave antenna and a typical rotary beam antenna. The difference between them is equal to the difference in the light emitted from an unshielded light bulb and from the same light bulb in a flash- light. The available energy is concen- trated in one direction, instead of be- ing sprayed all around the compass.
When transmitting, a rotary beam permits putting all your transmitter power in the desired direction. When receiving it gives an equal boost to incoming signals from the desired di- rection, while reducing the strength of signals arriving from other direc- tions, thereby reducing interference on the desired signal tremendously.
With high-frequency radio condi- tions now good and getting better, this is time for amateurs without beams to put them up and start beaming. This includes Novices on 21 me. (and 7 mc.).
Most rotary beam antennas use a 16-wave driven antenna and one or
72
two parasitic elements. Depending upon their adjustment, they accept power from the antenna and re-radi- ate it to modify the radiation pattern of the antenna alone.
A 2-element parasitic beam consists of the driven element and one para- sitic element. When the parasitic ele- ment is made 5% shorter than the antenna and is spaced about 0.1 wave- length in front of the antenna, it func- tions as a director. A director increases the power radiated in the forward di- rection from the antenna 3.5 times (5.5 db). At the same time, the signal ra- diated in other directions is sharply reduced.
Making the added element 5% longer than the antenna and spacing
Fig. 1. A comparison of the radiation patterns of a half-wave (A) antenna and (B) that obtained with a rotary beam antenna.
‘AXIS OF ANT.
y HERBERT S. BRIER, W9IEGO
it 0.15 wavelength behind the antenna changes it to a reflector. Forward gain will then be about three (4.8 db), again with reduced signals in other directions.
Adding both a reflector and a di- rector to the antenna results in a power gain of seven to eight (8 to 9 db) and a front-to-back ratio of 100:1 (20 db), if the parasitic elements are spaced 0.15 to 0.2 wavelength from the antenna element. More parasitic ele- ments may be added, but the size of the array goes up much faster than its gain does. Therefore, few amateurs use more than three elements for fre- quencies below 30 mc.
For comparison purposes, a typical 2-element, 14-mc. beam will consist of a 33’ long antenna and a 31’ 4” direc- tor seven feet in front of it. A 3-ele- ment beam will have a 34’ 6” reflector in addition and will be about 20 feet long. Parasitic arrays for the other amateur bands will be proportionately larger or smaller. It should be noted, however, that none of these dimen- sions is to be considered “final.” Many factors can combine to change dimen- sions in an actual beam.
Shortened Beams
For the average amateur with the room for it and the facilities to sup- port and rotate it, there is little doubt that a full-size rotary beam comes close to being the ideal antenna. The rub is that there are many circum- stances that make it impossible to erect one, even for the 10-meter band. One of them is lack of room. Another is the unhappy fact that a beam that
RADIO & TELEVISION NEWS
looks like a streamlined beauty to a ham, usually looks ten times as large and one-tenth as beautiful to his wife, landlord, parents, or neighbors.
To help overcome these circum- stances, shortened beams may be used. They take advantage of the fact that any electrical conductor has capacity, inductance, and resistance distributed throughout its length. When an an- tenna is cut to operate at a certain frequency, its inductive and capacitive effects neutralize each other, and the antenna readily accepts and radiates power at the desired frequency.
An antenna shorter than the proper length appears as a capacitive react- ance to the exciting frequency, and this reactance must be tuned out in some manner before the antenna will accept power. This can be done by cutting the antenna in half and in- serting a loading coil of the proper inductance.
In a parasitic beam, the reflector and director elements can be short- ened in the same manner, remember- ing to resonate them 5% below and above the antenna resonant frequency.
Loading an antenna element in this manner reduces its radiation resist- ance somewhat, compared to a full- size antenna, because it has less ac- tive radiating area. In the absence of losses, and assuming equal power in- put, this reduction would cause a cor- responding increase in antenna current to maintain the same radiating effi- ciency.
Unfortunately, all antennas do have losses, and even the best loading coils have higher losses than the sections of antenna they replace. These losses reduce the amount of power available to be radiated; consequently, a short- ened antenna is not quite as efficient as a full-size one. The difference is not as great as some skeptics would have you believe. Naturally, however, shortening should not be carried too far.
Carefully checking all available in- formation on the effect of shortening elements in parasitic arrays indicates the following: at first, as the elements of normal construction are shortened, the efficiency drops off quite slowly from that of a full-size beam. As the process continues, the cfficiency starts dropping off more rapidly, and by the time element lengths have been cut in half, output is down about 40%. Be- yond this point, output drops off very rapidly.
Of course, the foregoing pre-sup- poses low-loss construction and care- ful tuning after each adjustment of element lengths.
One way to reduce the size of the loading coil, and thus the losses, in shortened elements is to make the ele- ments of large diameter tubing. Do- ing so increases their effective capac- ity, which tunes the coils. This is done automatically in practical arrays, because fairly large diameter elements of aluminum tubing are used anyway so that they will be self supporting and will not fiep around in the wind.
January, 1957
SPECIFICATIONS ON COMMERCIAL SHORTENED BEAM ANTENNAS
Gonset Company, 801 South Main Street, Burbank, California. Makers of the Gonset “Bantam” 2-element beams for the 14-, 21-, and 28-mc. amateur bands, featuring “bow-tie” element construction.
ELEMENT BOOM GAIN APPROX. BAND LENGTH LENGTH F/B RATIO PRICE 14 mc. 166” 10’ Almost equal $59.50 to full-sized 2- element beam Almost equal 59.50 to full-sized 2- element beam Almost equal 44.50 to full-sized 2- element beam
21 me. 166” 10’ 28 mc. 10’7” 5’
Fed with 52-ohm coaxial cable (RG-8/U), not supplied.
Mosley Electronics, Inc., 8622 St. Charles Rock Road, St. Louis 14, Missouri. Makers of the “Vest-Pocket” shortened 2- and 3-element beams for the 7-, 14-, 21-. and 28-mc. amateur bands. Center-loaded low-loss coils weather protected in clear acrylic cases. LONGEST BOOM APPROX. BAND MODEL ELEMENTS ELEMENT LENGTH GAIN F/B RATIO PRICE 7 mc. VPA40-2 36’ 1%” 1410” 5 db 19 db $74.95 14 mc. VPA20-2 22'10%" 6° 20 db "44.73 14 mc. VPA20-3 23’ 1%” 12’ 28 db 66.37 21 or VPAI1015-2 19/1142” 46” 15 db 39.89 28 mc." 21 or VPA1015-3 28 mc.* *May be adjusted to operate in either band 7,14, VPA-3B 21 mc. (triband) 4 36’ 15’ 20 db 46 VPA1020 28mc. (dualband) 6 22’ 6” 12’ 72 db 28 db 216 VPA1520 28mc. (dualband) 6 22’ 6” 12’ 72 db 28 db
All Mosley beams fed with 52-ohm coaxial cabie (RG-8/U), not supplied.
13711%” 10’ 20 db 59.68
Radio Specialties, Inc., 652 Union St., Brooklyn, N. Y. Makers of 2- and 3-element “Shortbeams” for the 7-, 14-, and 2l-mc. amateur bands. Center-loaded with low-loss coils weather protected with Bakelite covers.
LONGEST BOOM APPROX. BAND MODEL ELEMENTS ELEMFNT LENGTH GAIN F/B RATIO PRICE 7 mc. RS2-40 33’ 4.4 db 15 db $74.95 14 mc. RS2-20 16’ 4.4 db 15 db 49.95 14 mc. RS3-20 16’ 4.8 db 20 db 59.50 21 mc. RS2-15 13’ 4.4 db 15 db 44.95 21 mc. RS3-15 13’ 4.8 db 20 db 54.95 Also available are dual 2-element “Shortbeams” for any combination of the above bands and a 3-element, 14-, 21-, and 28-mc. “3 Bander,” using four special loading devices in each of its 28’ elements. All Radio Specialties beams fed with 52-ohm coaxial
cable (RG-8/U), not supplied.
Telrex, Inc., Asbury Park, N. J. Makers of “Super Minibeams” for the 3.5- to 28-mc. amateur bands. Features high strength and high gain in minimum practical size.
LONGEST BOOM APPROX. BAND MODEL ELEMENTS ELEMENT LENGTH GAIN F/B RATIO PRICE 3.5mc. 80-M-370 2 64’ 3.2 db 15 db $370.00 7mc. 40-M-365 2 46’ 3.4 db 16 db 180.00 14mc. 20-M-56-79 2 29’ 4.8 db 14 db 79.50 21 mc. 15-M-56-67 2 18’9” 610” 4.8db 14 db 67.50 28 mc. 1030-S 3 13°7” 9’ 7 db 18 db 36.50 “Hairpin” loading stubs supported along the center boom, rather than loading coils, are used to resonate the higher-frequency “Super Minibeams.” All Telrex beams are fed with 52-ohm coaxial cable (RG-8/U), not supplied.
World Radio Laboratories, Inc., 3415 West Broadway, Council Bluffs, lowa. At present, has only one shortened beam in its line. It is for the 14-mc. band and features two
low-loss coils per element for loading. LONGEST BOOM APPROX.
BAND MODEL ELEMENTS ELEMENT LENGTH PRICE 14 mc. “Globe Spannette” 3 21’ 18” $54.95 May be fed with any standard transmission line from 52-ohm coaxial cable to 450-ohm twin-lead. Line not supplied. Also available is a 3-element, 14-, 21-, and 28-mc. beam, using four special loading devices in each element. Boom length 20’. Price $99.75.
Sl i a
This photo of the center of a Mosley “Vest Pocket” beam shows the antenna loading coil and how power from the RG-8/U transmission line is coupled into it. The load- ing coil for the reflector and director are similar, except that the coupling link is omitted. Method of supporting elements to boom and boom itself are also shown.
A further increase in element capac- ity can be obtained by making each half element of two, fanned-out lengths of tubing joined together with a cross- piece at the ends. A complete element then looks like a bow tie, with the loading coil representing the knot.
Another approach to the problem of reducing coil losses is to use two load- ing coils per element, one near each end, instead of one in the center. The closer to the end of the element a coil is placed, the less current it car- ries; therefore, coil losses should be less. On the other hand, there is also less capacity across the coil to tune it, making more turns necessary. The best compromise between these con- flicting factors occurs when the coils are placed approximately half way be- tween the center and each end of the element.
The different manufacturers of the shortened arrays listed in the accom- panying table take advantage of all these methods to shorten elements lengths 18% to 50%.
Covering Several Bands All conventional parasitic type an-
The 3-element Telrex “Super Minibeam” of WSVEY, Hillsboro, Il. mounted atop a 50-foot TV antenna tower and rotated with a TR-4 rotator. Installation has been in operation several years.
tennas work efficiently over only a relatively narrow range of frequen- cies, approximately plus or minus 75 ke. of the design frequency on 14 mc. for a typical shortened beam, with proportionate coverage on the other bands. To cover additional bands, therefore, requires stacking separate antennas Christmas-tree fashion at least five feet apart, or use of 2- or 3- band arrays. They consist of independ- ent antenna systems mounted on a single support boom and adjusted for minimum interaction between them.
Support and Rotation
The nicest thing about shortened beams is that they can be supported on properly guyed TV antenna towers. Also, up to three elements on 14 mc. or two on 7 me. can be rotated by a good heavy-duty TV antenna rotator. Among the suitable rotators for the purpose are the C-D-R AR-22 and TR-4. The latter is available with spe- cial heavy-duty gears as model HD-4. Equivalent rotators of other manufac- turers are equally satisfactory. For multi-band installations, rotators de- signed especially to turn amateur
beams are required, unless the beam drive shaft is brought within reach of the operator for manual rotation.
How high should the antenna be erected? The stock answer to this question is “as high as_ possible.” Translated into actual figures, every foot of height up to 50 feet helps, es- pecially in working DX. Below 30 feet, results usually drop off rather rapidly. Above 50 feet, improvement comes slowly, unless the added height boosts the antenna above utility wires and other obstructions.
Ideally, the antenna should be erected at the desired height in the center of a large field completely free from all obstructions. In practice, we put it on top of the house or garage or in the back yard. If the antenna is put on the roof of a building and the building is of steel frame construction, effective antenna height is usually its height above the roof, rather than its height above the earth. Under these circumstances, the height of the build- ing is useful only to help clear nearby obstructions. Over a wooden building, however, the effective antenna height approximates its height above the earth.
Expected Results
It would be nice if it were possible to predict just how much better re- sults will be obtained when using a beam antenna, compared with those obtained from a non-directional one. Unfortunately, this is not possible, be- cause so many unpredictable variables are involved. However, many ama- teurs who have never worked a for- eign DX station before erecting a simple beam are able to work them regularly with a beam. What you can expect is that, with your beam, you will hear signals much more clearly, and you will get out more consistently. In other words, those periods in which you cannot raise anyone, no matter what you do, come much less fre- quently and last a shorter length of time with a beam. —30—
The 3-element. 20-meter “Globe Spannette” of World Radio Lab. uses a pair of low-loss loading coils in each element. “Carpet beaters” at the ends of elements act as vibration dampers.
RADIO & TELEVISION NEWS
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75
NS ly aun)
74
thing, he was not chattering away
like a magpie, and this in itself was abnormal; moreover, he seemed to be lost in thought as he worked away at the service bench. alongside Mac, his boss. Finally the latter put down his solder gun and demanded:
“What’s eating you this morning? Did Margie stand you up last night, or did some ham in Lower Slobbovia give you a bad signal report on that glori- fied diathermy machine you call a transmitter?”
“You know I never have woman trouble,” Barney boasted; “but you’re pretty warm with that second guess. I’ve got a bug in my transmitter that’s about to drive me goofy. About three months ago the transmitter started blowing fuses. At first this would hap- pen only about once a week, although occasionally two fuses might go in a quarter of an hour; but lately the con- dition has grown much worse. Last night I couldn’t say, ‘Boo,’ into the mike without going off the air. And I'm using fuses plenty heavy enough to carry the rated current drawn by the transmitter.”
“Does this happen on c.w. or phone ?”
“Always on phone, and that’s what has me sweating,” Barney said rue- fully. “I’m afraid it’s the modulation transformer insulation breaking down between a winding and the core. If it is, that’s going to make an awful dent in my bank account; but still worse is the fact that I’m not positive that the transformer is causing the trouble. If I bought a new modulation transform- er and then found the trouble still per- sisted, I'd be ready for one of those white jackets with the wraparound sleeves.”
“Does the fuse just let go quietly, or are there other symptoms that show up the instant it blows?”
“T always hear a sort of spitting noise that sounds like an arc-over, but I know it’s not in the plate tank ca- pacitor or the antenna-loading capaci- tor, for I’ve been looking right at these two in a darkened room when the fuse
Bitsins. was not himself. For one
76
By JOHN T. FRYE TURN ABOUT
let go, and I didn’t see any fire. The arc must be somewhere out of sight which again points at the modulation transformer.”
“Let me see now,” Mac said as he rubbed a thumb along the sharp out- line of his chin; “the same high volt- age flows through the centertap of the primary of your modulation trans- former to the plates of the modulator tubes and also goes through the sec- ondary winding to the plate of the final amplifier tube. Is that right?”
“Check,” Barney said. “That means either the primary or secondary wind- ing could short to the core and cause the trouble; but a short could develop a lot of other places, too. Either one of the modulator tubes could develop an internal short; so could the final tube; the plate-blocking capacitor in the final tank circuit could arc over internally; some of the feedthrough in- sulators could be breaking down—oh there are lots of places for an arc to occur that could blow a fuse. That’s what makes it so headachy.”
Mac walked over to a drawer, pulled it open, and took out a half-dozen little porcelain sockets. ‘Maybe you can pin- point the source of the trouble with these,” he suggested. “They take standard screw-type panel lamps. It’s my idea you insert lamps of appropri- ate current carrying capacity at stra- tegic points in the circuit and then see which lamp or lamps blow when the arc occurs. Lamps rated at 150, 250, and 500 milliamperes should take care of about all the currents in the high- voltage part of your rig.”
“Hey! Wait a minute! I think you've got something,” Barney said with en- thusiasm. “You mean I can put one lamp in the lead going to the center- tap of the primary of the modulation transformer. Another could go in the ‘B-plus’ lead of the secondary of that transformer, and still another could be in the other lead of this winding that goes up to the final amplifier. If the lamp in the primary lead goes out when the short circuit occurs, I can forget the rest of the circuit and con-
A RADIO & TELEVISION NEWS
centrate on the plate circuit of the modulator tubes. On the other hand, if the lamp burns out in the ‘B-plus’ lead to the secondary, but the one in the other lead of this winding stays okay, I can be sure I have an arc be- tween the secondary winding and the core. And if the one burns out in the lead going to the final amplifier, I'll know—hey, wait a minute; since the same current will be flowing through this lamp and the one in the other lead as well, one lamp is as likely to go first as the other if the trouble is in the final amplifier.”
“You've got a point there, but that’s why I suggested lamps of different current ratings. Suppose you put a 500 ma. lamp in the ‘B-plus’ lead and a 250 ma. lamp in the lead going to the final amplifier. A short circuit be- tween the winding and the core will take out the 500 ma. lamp quickly; but if the short happens on beyond the 250 ma. lamp, it will burn out and leave the 500 ma. lamp okay. Another point is this: if you can arrange the lamps so that you can see them and still have a little separation between them, the flash of the overloaded lamp, even though seen out of the tail of your eye, will reveal which part of the circuit is carrying too much current. Once you have established that, you can use more lamps, strategically placed, to corner the trouble in the smallest possible unit of the circuit. In using lamps in some leads, it may be easier to solder them in place rather than employ these sockets.”
“Well, I'll surely give it the old col- lege try tonight,” Barney promised as he slid the sockets and several assort- ed pilot lamps into a paper sack. “This thing has worn me down until I’m ready to try anything. If I don’t find it tonight, I’m going to call on Madam Miranda, the crystal ball gazer, to- morrow.”
* ae aa cd +
When Mac came down to open up the shop the next morning, he was astonished to find it already open. Barney greeted him at the door with a dazzling grin spread all over his freckled Irish face.
“Are you ever a right thinker!” he exclaimed. “Thanks to that suggestion about the lamps, I found my rig trou- ble; and it was not the modulation transformer!” ‘
“What was it?” Mac asked.
“It was a nasty little feedthrough insulator that had cracked and was arcing to the chassis down inside out of sight. This insulator fed the voltage from the high side of the modulation transformer to the final amplifier; so both the d.c. voltage and the audio voltage were impressed upon it. A lamp on one side of the insulator went out every time I heard the arc, but the one on the other side never did. When I took the insulator apart, it was very easy to see where the arc had black- ened the chassis and charred one of the little paper anti-strain washers. I replaced the insulator and then could
(Continued on page 96)
RADIO & TELEVISION NEWS
Jan
HOW MANY CAN YOU ANSWER “YES?”
January, 1957
1. Do you wish to extend your experience in electronics systems?
2. Would you like to instruct others in advanced fire control systems and labora- tory techniques?
3. Would you like to handle a responsible position representing a leading electronics organization?
4.Do you believe that you can accurately relate your findings and studies in te nical language?
S. Are you interested in such devices as an- alog computers, digital computers, power supplies, transmitters, receivers, and mi- crowave antennas?
6.Do you enjoy working with people?
If you can answer “yes” to four of the above questions and have an Electrical Engineering or Physics degree, chances are that you can qualify for one of the several engineering positions in the Hughes Field Engineering department. In addition to giving you well-rounded experience in electronic systems and con- trols, Hughes offers you training at full salary, moving and travel allowances, per diem expenses, and many other benefits. For further information write Mr. W. A. Barnes at the address below.
RESEARCH AND DEVELOPMENT LABORATORIES SCIENTIFIC STAFF RELATIONS
Hughes Aircraft Company, Culver City, Calif,
‘ | | Ee |p R ts for Hi- A sreat high fidelity oe tape recorders fromaname | | : eg
Tests conducted in an actual living that stands for recision room readily confirmed the fact that p see the reason higher powered amplifiers sound better is because realistic music requirements require in excess of 25 watts with efficient speakers, and in excess of 100 watts with the most in- tape deck for the components owner efficient speakers. For example, with aeene 2 gala on the go the AR-Janszen combination it was impossible to obtain realistic piano re- production on a direct comparison with the original loudness level with less than 100 watts of power. On com- mercial recordings in which volume compression is used, 50 watts of ca- pacity was adequate. However, on tapes made directly from live sources, with dynamic program material, occa- sional overload was experienced with a 50-watt amplifier even with mod- erately high efficiency speakers. The most significant fact in these experiments was that the visual over- load on the scope correlated with
‘Assntgh traces of roughness in the reproduc- “Dual Professional” Basic ies Recorder : : : . ;
Push-button, custom-installation tape deck ready to tion showing that overload 1S audible. combine with present sound system. At 714” equals The type of distortion which was evi-
or exceeds wel eeeggg” VE Sp ingen agg ei denced by overload was that which is Reisen track oo haw pA Sag Si yma syn- attributed frequently to “record break- chronous motor. $329.50 up,” “lack of stylus tracking,” and similar excuses. Much of the criticism TK-820 “Dual of sound reproduction which has been Professional” Portable levelled at program sources seems to Same controls and specs arise from inadequate power capacity Siete with Hi- - ag Reson in the playback systems. This over- er System in travel case. load condition is particularly offensive saree Tiads coker gu0e! to the ear when the associated ampli- ome $399.50 fier has a poor recovery characteristic
under overload conditions.’ cr-820 “Consolette” It is suggested that audio enthusi- 4 : . asts who have an oscilloscope avail- with Hi-Five Speaker System “ Nba See able try the tests outlined in this Bg Rete agg ney Eatinsey” Portable article. It is amazing at how low an
unit housed in furniture- Three-speaker port- ‘ =f. rs “ weight Korina cabinet. able dual track with a average level some visual evidences of
ng ted at peoustionl ee et ae Sew, clipping appear. As the playback level chamber gives magnificent quality, 714” and 3%” ee of the system is increased, many loud sadio quality. $408.08 speeds, magnificent passages will be seen to cause ampli-
ae ea s, fier overload even when they do not sound tremendously loud. Once the type of sound associated with overload is recognized, it will be found that many systems overload very frequent- ly. This is particularly true of demon-
You're always sure with strations in sound rooms and audio shows where demonstration levels far
exceed the capacity of the equipment,
DEJUR-AMSCO CORPORATION, but where large crowds create such
LONG ISLAND CITY 1, N. Y. a high ambient noise level that demon-
COATS, Ee : stration levels are increased above
ap hap pare 3 aye, normal requirements. The problem of DEJUR INTERNATIONALE, : bear, . : P “at
insufficient amplifier power capability
GMBH, WEST GERMANY , : : Audio Equipment is one which will be more acute in the future since the trend toward
pon -SEND COUPON FOR COMPLETE SPECIFICATIONS ————~ greater recorded dynamic range con-
a j s. Th wer requirements of the DeJUR-AMSCO CORPORATION, Dept. RN1, 45-01 Northern Blvd., L.L.C. 1, N.Y. -oesen acy ak > te excess of 100
Please send me, without obligation, complete specifications. watts, particularly if speaker efficien- cies are further reduced.
consolette for music lovers
Con ™ eel FFE FS 4) ee,
Name REFERENCES 1. Hafler, David: “Control of Amplifier
July 1955.
P 2. Hafler, David: “A 50 Watt Power Am-
City plifier,’” Rapio & TELEVISION NEws, June 1956.
I
!
!
i
f
!
; Address Damping Factor,” RapI0o & TELEVISION NEWS, |
i
—
78 RADIO & TELEVISION NEWS
RCA offers you the finest training
at home | Radio-TV electronics,
TV servicing,
SEND FOR THIS FREE
BOOK NOW!
® RCA INSTITUTES, INC.
4A SERVICE OF RADIO CORPORATION of AMERICA 350 WEST FOURTH STREET, NEW YORK 14, N.Y.
January, 1957
The instruction you receive and equipment you get (and keep) will start you on your way. Pay- as-you-learn. You pay for only one study group at a time. This 52 page book contains complete information on Home Study Courses for the be- ginner and the advanced student.
RCA Institutes, Inc., Home Study N-17.
350 West Fourth Street New York 14, N. Y. Without obligation, send me FREE CATALOG VETERANS on Home Study Courses in Radio, Television
and Color TV. No salesman will call. person
— Please Prin! CHECK HERE
HEATHKIT ETCHED CIRCUIT, PUSH-PULL
5” Oscilloscope Kit COLOR TV
The previous Heathkit oscilloscope(Model O-10) which was already a most remarkable instrument, has been im- proved even further with the release of the Heathkit Model O-11. It incorporates all the outstanding features of the preceding model, plus improved vertical linearity, better sync stability, especially at low frequencies, and much-improved over-all stability of operation, including less vertical bounce with changes in level. These improve- ments in the Model O-11 circuit make it even more ideally suited for color TV servicing, and for critical observations in the electronic laboratory. Vertical response extends from 2 CPS to 5 MC without extra switching. Response only down 2.2’ DB at 3.58 MC. The 11-tube circuit features a SUP1 cathode-ray tube. Sync circuit functions MODEL O-11 effectively from 20 CPS to better than 500 kc in five steps. Modern etched circuit boards employed in the oscillo- Shpg. Wt . . . , " 21 Lbs scope circuit cut assembly time almost in half, permit a level of circuit stability never before achieved in an oscilloscope of this type, and insure against errors in assembly. Both vertical and horizontal output amplifiers are push-pull. Built-in peak-to-peak calibrating source — step-attenuated input — plastic molded capacitors and top- quality parts throughout — pre-formed and cabled wiring harness — and numerous other “extra” features. A pro- fessional instrument for the serviceshop or laboratory. Compare its specifications with those of scopes selling in much higher price brackets. You can’t beat it!
@e@ee2eeeeeeoeeeeeee20e02080e08008ee%
FEWER DOLLARS BRING MORE REAL QUALITY.
@ Factory-to-you sales eliminate extra profit margin. @ “Build-it-yourself"' eliminates labor charge.
@ Heath purchasing power cuts component costs.
PERSONAL SERVICE ASSURES CUSTOMER SATISFACTION.
@ You deal directly with the manufacturer. @ We are interested in you before and after sale.
Hecithekit
ARE YOUR BEST BUY...
PROVEN DESIGNS MEAN RELIABLE
PERFORMANCE.
@ Research and development efforts concentrated on kits only.
@ All kits guaranteed to meet advertised specifications.
EVERY KIT BACKED BY WORLD-WIDE
REPUTATION.
@ The world's largest manufacturer of electronic equip- ment in kit form.
@ Producer of more than a million electronic kits for the home workshop and industry.
EASY TIME-PAYMENT PLAN TO FIT YOUR
BUDGET.
RADIO & TELEVISION NEWS
Yow. HEATHKIT ETCHED CIRCUIT
5’ Oscilloscope Kit
Pecial int oo eoL ¢ merest is in servicing, Brand new model with improved performance
Qh-fidelity, of ; ’ [Ust exper; : ° ° fill your needs. iw oom we specifications.
plete ham stati
GREATEST SELECTION
Whether your parti, ham-radio, hi Povey,
an entire Full 5” scope for service work at a remarkably
low price.
sharp white lettering, some ideq
* sk Attractively styled front panel in charcoal gray with vality elec. *K
Easy to build from step-by-step instructions and large pictorials. Not necessary to read schematic.
This new and improved oscilloscope retains all the outstanding features of the
preceding model, but provides wider vertical frequency response, extended sweep-
generator coverage, and increased stability. A new tube complement and improve-
ments in the circuit make these new features possible. Vertical frequency response
is essentially flat to over 1 mc, and down only 1% DB at 500 ke. The sweep
generator multivibrator functions reliably from 30 to 200,000 CPS, almost twice
the coverage provided by the previous model. Deflection amplifiers are push-pull,
and modern etched circuits are employed in critical parts of the design. A SBP1
cathode-ray tube is used. The scope features external or internal sweep and sync,
one volt peak-to-peak reference voltage, 3-position step-attenuated input, adjustable
spot-shape control, and many other “extras” not expected at this price level. A
calibrated grid screen is also provided for the face of the CRT, allowing more
precise observation of wave shapes displayed. The new Model OM-2 is designed jopeL OM-2
for general application wherever a reliable instrument with good response charac-
teristics may be required. Complete step-by-step instructions and large pictorial 4 Yc +.
diagrams assure easy assembly. Shpg. Wt.
21 Lbs.
SHCHCOSHSHSHSHSHSHSSHSHSHSHSHSHESHSOSHSHSHSHSBSHSHSSSHSHHSHSHSHSHSHHSHSSHHSHOHSEESESEEE®E
HEATHKIT LOW CAPACITY PROBE KIT Oscilloscope investigation of high frequency, high im- pedance, or broad bandwidth circuits encountered in television requires the use of a low-capacity probe to prevent loss of gain, circuit loading, or waveform dis- tortion. The Heathkit low-capacity probe may be used with your oscilloscope to eliminate
these effects. It features a variable cap- No, 342 acitor, to provide correct instrument
impedance match. Also, the ratio of $350
‘attenuation can be varied. Shpg. Wt. 1 Lb.
HEATHKIT SCOPE DEMODULATOR PROBE KIT Extend the usefulness of your oscilloscope by employing this probe. Makes it possible to observe modulation of RF or IF carriers found in TV and radio receivers. Functions much like an AM detector to pass only modu- lation of signal, and not the signal itself. Among other uses, it will be helpful in alignment
work, as a signal tracer, and for deter- NO. 337-C mining relative gain. Applied voltage $ 50 limits are 30 volts (RMS) and 500 3 e volts DC. It uses an etched circuit shpg. we. 1 tb. board to simplify assembly.
January, 1957
HEATHKIT ELECTRONIC SWITCH KIT
This handy device allows simultaneous oscilloscope observation of two signals by producing both signals, alternately, at its output. It features an all-electronic switching circuit, with no moving parts. Four switching rates are selected by a panel switch. Provides actual gain for input signals, and has a frequency response of + 1 DB from 0 to 100 ke. Sync output provided to control and
Stabilize scope sweep. Will function at signal levels as MODEL S-3 low as 0.1 volt. This modern device finds many ap-
plications in the laboratory and service shop. It $9195 employs an entirely new circuit, and yet is priced °
lower than its predecessor. Shpg. Wt. 8 Lbs.
HEATHKIT VOLTAGE CALIBRATOR KIT
This entitely new voltage calibrator produces near-perfect square wave signals of known amplitude. Precision 1% attenuator resistors assure accurate output amplitude, and multivibrator circuit guaran- tees good, sharp square waves, as distinguished from clipped sine waves. Output frequency is approximately 1000 CPS. Fixed outputs selected by panel switch are; .03, 0.1, 0.3, 1.0, 3.0, 10, 30, and 100 volts Pepe 2 de ty age a of —
Signal amplitudes by comparing to known peak-to-
peak output of VC-3 on an oscilloscope. Will also MODEL VC-3 double as a square wave generator at | cycles for $ 50 determining gain, frequency response, or phase- 12 ° shift characteristics of audio amplifiers. Equally sho. we. 4 tbs. value in the laboratory or in radio and TV service : shops.
Voltmeter Kit
The fact that this instrument is the world’s largest-selling VTVM says a great deal about its accuracy, reliability, and overall quality. The V-7A is equally popular in the laboratory or service shop, and represents an unbelievable test equipment bargain, without a corresponding sacrifice in quality. Its appearance reflects the performance of which it is capable. A large 442” panel meter is used for indication, with clear, sharp calibrations for all ranges. Front panel controls consist of a rotary function switch and a rotary range selector switch, zero-adjust, and ohms- adjust controls. Precision 1% resistors are used in the voltage divider circuits and etched circuits are employed for most of the circuitry. This makes the kit much easier to build, eliminates the possibility of wiring errors, and assures duplication of laboratory instrument performance. This multi-function VIT'YM will measure AC voltage (rms), AC voltage (peak-to-peak), DC voltage, and re- sistance. There are 7 AC (rms) and DC voltage ranges of 0-1.5, 5, 15, 50, 150, 500, and 1500. In addition, there are 7 peak-to-peak AC ranges of 0-4, 14, 40, 140, 400, 1400, and 4000. 7 ohmmeter ranges provide multiplying factors of X1, X10, X100, X1000, X10K, X100K, and X1 meg- ohm. Center-scale resistance readings are 10, 100, 1000, 10K, 100K ohms, 1 megohm, and 10 megohms. A DB scale is also provided. The precision and quality of the components used in this VTVM cannot be duplicated at this price through any other source. Model V-7A is the kind of instrument you will be proud to own and use.
/VOLT VOM KIT § 20,000 ohms-per-volt DC and 5,000 ohms-per-volt AC. Measuring , 1500, and 5000 volts for both AC and DC. Also measures current eres, 15 ma, 150 ma, 500 ma, and 15 a. Resistance ranges provide 10,000, resulting in center scale readings of 15, 15,000, and 150,000 10 db to +65 db. Housed in attractive black bakelite case with le instrument provides a total of 25 meter ranges MODEL MM-1 ys a Sensitive 50 microampere, 444” meter and $2950 er resistors. Requires no external power, and is, © : applications where no AC power is available. Shpg. Wt. 6 Lbs.
fe
HEATHKIT HANDITESTER KIT
The Model M-I measures AC or DC voltage at 0-10, 30, 300, 1000, and 5000 volts. Direct current ranges are 0-10 ma, and 0-100 ma. Ohmmeter ranges are 0-3000 (30 ohm center scale) and 0-300,000 ohms (3,000 ohms center scale). Uses a 400 microampere meter for sensitivity of 1000 ohms-per-volt. A very popular test device for the home experimeter, electricians, and appliance repairmen, and for use as an “‘extra’’ instru- ment in the service shop. Its small size and rugged construction make it perfect for any portable application. MODEL M-1 Easily slips into your tool box, glove com-
partment, coat pocket, or desk drawer. Top $1]45° quality, precision components employed * throughout. Shpg. Wt. 3 Lbs.
RADIO & TELEVISION NEWS
HEATHKIT NEW AUDIO VACUUM TUBE
CONTROLLED Quauiry , Voltmeter Kit
Incomin ‘ 9 Parts inspectio ™ and inspecti on of ma-
terial comin 9 Off of our ow, “ ° n Production li build-it-yoursel¢" ine assures %* Brand new circuit for extended frequency response
1 kit that contains all the components vor and added stability. uU
% Ten accurate ranges from 0-.01 to 0-300 volts.
* Modern, functional panel styling. “On-off” switch Varantees easy. at both extreme ends of range switch. © performance,
each new kit g mS and religb|
This brand new AC vacuum tube voltmeter emphasizes stability, broad frequency re- sponse, and sensitivity. It is designed especially for audio measurements, and low-level AC measurements in power supply filters, etc. Employs a cascode amplifier circuit with cathode-follower isolation between the input and the amplifier, and between the output stage and the preceeding stages. An extremely stable circuit with high input impedance (1 megohm at 1000 CPS). Response of the AV-3 is essentially flat from 10 CPS to 200 kc, and is usable for tests even beyond these frequency limits. Increased damping in the meter circuit stabilizes the meter for low frequency tests. Nylon insulating bushings at the input terminals reduce leakage, and permit the use of the 5-way Heath binding post.
The extremely wide voltage range covered by the AV-3 makes it especially valuable not only in high-fidelity and service work, but also in experimental laboratories. AC (RMS) voltage ranges are 0-.01, .03, .1, .3, 1, 3, 10, 30, 100, and 300 V. Decibel ranges cover MODEL AV-3
~—52 DB to +52 DB. An entirely new circuit as compared to the previous model. Em- $ 95 29 - Shpg. W.
ploys 1% precision multiplier resistors for maximum accuracy. Handles AC. measure- 5 Lbs,
ments from a low value of one millivolt to a maximum of 300 volts. @ee0e00000000000000008000800000000000000000800000000008008080808686
HEATHKIT AUDIO WATTMETER KIT HEATHKIT AUDIO ANALYZER KIT
This instrument measures audio power directly at 4, 8, 16, or This multi-function instrument combines an AC VTVM, an audio wattmeter, and an intermodulation analyzer into one
600 ohms. Load resistors are built in. Covers 0-5 MW, 50 case, with combined input and output terminals and built-in
MW, 500 MW, 5 W, and 50 W full scale. Provides 5 switch- selected DB ranges covering from —10 DB to +30 DB. Large 414" 200 microampere meter and precision multiplier resistors insure accuracy. Frequen- MODEL AW-1 cy response is + 1 DB from 10 CPS to 250 kc.
Functions from AC power line. Use in the $2950 audio laboratory or in home workshop. Shpg. Wt. 6 Lbs.
HEATHKIT HARMONIC DISTORTION METER KIT
The HD-1 is equally valuable for the audio engineer or the Serious audiophile. Used with a low-distortion audio signal generator, this instrument will measure the harmonic content of various amplifiers under a variety of conditions. Functions between 20 and 20,000 CPS, and reads distortion directly on the panel meter in ranges of 0-1, 3, 10, 30, and 100 percent full scale. Built-in VTVM for initial reference settings and final distortion readings has voltage ranges of 0-1, 3, 10, and 30 volts. 1% precision re- MODEL HD-1 —— employed for maximum accuracy.
eatures voltage regulation and other “‘ex- tras’’. Meter calibrated in volts (RMS), per- $4g95° cent distortion, and DB. Shpg. Wt. 13 Lbs.
January, 1957
high and low frequency oscillators. The VTVM ranges are -O1, .03, .1, .3, 1, 3, 10, 30, 100, and 300 volts (RMS). Wattmeter ranges are-.15 MW, 1.5 MW, 15 MW, 150 MW, 1.5 W, 15 W, 150 W. IM scales are 1%, 3%, 10%, 30%, and 100%. Provides in- MODEL AA-1 ternal load resistors of 4, 8, 16, or 600 ohms. $4995 A valuable instrument for the engineer or e Serious audiophile. Shpg. Wt. 13 Lbs.
HEATHKIT AUDIO OSCILLATOR KIT
Producing both sine waves and square waves, the Model AO-1 covers a frequency range of 20 to 20,000 CPS in three ranges. An extra feature is thermistor regulation of output for flat response through the entire frequency range. AF output is pro- vided at low impedance, and with low dis-
tortion. Produces good sine waves, and good,
clean square waves with a rise time of only MODEL AO-1 two micro-seconds for checking square wave
response of audio amplifiers, etc. Designed $245° especially for the serviceman and high- e fidelity enthusiast. A real dollar value in test Shpg. Wt. 10 Lbs. equipment.
HEATHKIT
* Les han 0.1% distortion — ileal for if work. sk Large 495" meter indicates oni
SK Step-type tuning
reeeescceooce = el ots eccececoce
HEATHKIT RESISTANCE _ _HEATHKIT CONDENSER
SUBSTITUTION BOX KIT _ _ SUBST!TUTION BOX KIT
1 contains 36 1 Lente This kit contains 18 RETMA stan —. bos 36 10% Panta : enser values that can be
ne tee d RETMA val- sehsted ta cary etch alas , from 0.00001 mfd to 0.22 mfd. ; ” Alle map he rated at 400 volts ance values aes t Stoetimenssicir pac’’+1s are MODEL CS-1 application: in ie, or pice $550 - of radio and TV nite’ ; . service work. Shpg. Wt. 2 Lbs.
di velopment MODEL DC-1 coamic 49550 ape 6%
Shpg. Wt. 3 kbs 2
HEATHKIT DECADE RESISTANCE Kit ‘
i Model DR-1 incorporates twenty 1 five rugged switches so that various
provide a total range ws eee
ohm steps. Switches are la beled “units,”
dreds,” “thousands,” and “ten thousands.” | it for
ohm-meter calibration in bridge circuits as test values
in multiplier circuits, etc,
HEATH COMPANY A Subsidiary of Deystrom, Inc. BENTON HARBOR 15, MICH.
Audio Generator Kit
This particular audio generator is “made to order” for high fidelity applications. It provides quick and accurate selec tion of low-distortion signals throughout the audio range. Three rotary selector switches on the front panel allow selection of two significant figures and a multiplier for determining audio frequency. In addition, it incorporates a step-type output attenuator and a continuously variable attenuator. Output is indicated on a large 442” panel meter calibrated in volts and in db. Attenuator system operates in steps of 10 db, corresponding with the meter calibration. Output ranges are 0-.003, .01, .03, .1, .3, 1, 3, and 10 volts rms. A “load” switch provides for the use of a built-in 600 ohm load or an external load of higher impedance when required. Output and frequency indi- cators accurate to within + 5%. Distortion is less than .1 of 1% between 20 cps and 20,000 cps. Total range is 10 cps to 100 kc. New engineering details combine to provide the user with an unusually high degree of operating effi- ciency. Oscillator frequency selected entirely by the switch method means that accurate resetability is provided. Com- parable to units costing many dollars more, and ideal for use in critical high fidelity applications, Shop and compare, and you will appreciate the genuine value of this pro- fessional instrument.
HEATHKIT AUDIO GENERATOR KIT
The Model AG-8 is a low cost, high performance unit for use in service shop, or home wor'chop. It covers the frequency range of 20 cps to | mcin five #:ges. Output is 600 ohms, and overall distortion will be less than .4 of 1% from 100 cpsthrough the audible range. Output is available up to 10 volts, under no load conditions, and output remains constant
within +1 db from 20 cps to 400 kc. A five- MODEL AG-8 step attenuator provides control of the out- $2950 put. Precision resistors are employed in the ° frequency determining network. Shpg. Wt. 11 Lbs.
HEATHKIT VARIABLE VOLTAGE
REGULATED POWER SUPPLY KIT
This power supply is regulated for stability, and the amount of DC output available from the power supply can be controlled manually from zero to 500 volts. Will provide regulated output at 450 volts up to 10 ma, or up to 130 ma at 200 volts output. In addition to furnishing B-plus, the power supply provides 6 volts AC at 4 amperes for filaments. Both the B-plus output and the filament output are isolated from
ground. Ideal power supply for use in experi- MODEL PS-3 mental work in the laboratory, the home work- $3550 shop, or the ham shack. Large 444” panel e meter indicates output voltage or current. Shpg. Wt. 17 Lbs.
RADIO & TELEVISION NEWS
PERFORMANCE
d had to be
res q re not ©xaggerated, Gnd that We SPecify per =
forma nce on be sure
HEATHKIT
Signal Generator Kit
* No calibration required with pre-aligned coils,
* Modulated or unmodulated RF output.
* 110 mc to 220 mc frequency coverage,
Here is an RF signal generator for alignment applications in the service shop or the home workshop. Thousands of these units are in use in service shops all over the country. Produces RF signals from 160 ke to 110 mc on fundamentals on five bands. Also covers from 110 mc to 220 mc on calibrated harmonics. RF output is in excess of 100,000 microvolts at low impedance. Output is controllable with a step-type and a continuously variable attenuator. Front panel controls provide selection of either unmodulated RF output or RF modulated at 400 cps. In addition, two to three volts of audio at approximately 400 cps are available at the output
terminals for testing AF circuits. Employs a 12AU7 and a 6C4 tube. Built-in power
supply uses a selenium rectifier.
MODEL $G-8
One of the most outstanding features about the Model SG-8 is the fact that it
can be built in just a few hours, even by one not thoroughly experienced in elec- tronics work. Complete step-by-step instructions combined with large pictorial diagrams assure successful assembly. Pre-aligned coils make calibration from an
external source unnecessary.
HEATHKIT LABORATORY GENERATOR KIT
This laboratory RF signal generator covers from 100 kc to 30 mc on fundamentals in five bands. The output signal may be pure RF, or may be modulated at 400 cycles from 0 to 50%. Provision for external modulation has been made. RF output available up to 100,000 microvolts. Output controlled by a fixed step and a variable attenuator. Output impedance is 50 ohms. Panel meter reads RF output or percentage of modulation. Incorporates voltage regulated B+ supply, MODEL LG-1 double shielding of oscillator circuits, copper $4895 plated chassis, and other “extras.” % Shpg. Wt. 16 Lbs.
HEATHKIT LINEARITY PATTERN GENERATOR KIT
This instrument supplies information for white dots, cross-hatch pattern, horizontal bar pattern, or vertical bar pattern. It feeds video and sync signals to the set under test, with completely con- trolled gain, and unusual stability. Covering channels 2 to 13, the LP-2 will produce 5 to 6 vertical bars and 4 to 5 horizontal bars. The dot pattern presentation is a must for the setting of color convergence controls in the color TV set. Panel provision made for external sync if desired. Use for adjustment of vertical and horizontal linearity, picture size, aspect MoOpeL LP-2 ratio, and focus. Power supply is regulated for i added stability. Essential in the up-to-date TV $9950 Service shop. 4 Shpg. Wt. 7 Lbs.
January, 1957
s 50 shoo. wr. ° & Lbs,
TOeaeReRPReRePeREREREBRERERERERREREREREARARRRRRR RRR
HEATHKIT TV ALIGNMENT GENERATOR KIT
This improved sweep generator model provides essential stability and flexibility for work on FM, monochrome TV, or color TV sets. Covers 3.6 mc to 220 mc in four bands. Provides usable out- put even on harmonics. Sweep deviation from 0-42 mc, depend- ing on base frequency. All-electronic sweep circuit eliminates unwieldy mechanical arrangements. Includes built-in crystal marker generator providing output at 4.5 mc
and multiples thereof, and variable marker MODEL TS-4A covering 19 to 60 mc on fundamentals and from
57 to 180 mc on harmonics. Effective two- $4950 way blanking. Shpg. Wt. 16 Lbs.
HEATHKIT CATHODE RAY TUBE CHECKER KIT
This instrument checks cathode emission, beam current, shorted elements, and leakage between elements in electro-magnetic picture tube types. It eliminates all doubt for the TV serviceman, and even more important, for the customer. Features its own self-contained power supply, transformer operated to furnish normal test voltages for the CRT. Employs spring-loaded switches for maximum operator protection. Large 444" meter indicates CRT condition on “‘good-bad” scale. Luggage-
type portable case ideal for home service calls. MODEL CC-1 Special “‘shadowgraph” test permits projection $9950 of light spot on screen. Also gives relative check °
of picture tube screen coating. Shpg. Wt. 10 Lbs,
Tube Checker Kit
This fine piece of test gear checks tubes for quality, emission, shorted elements, open elements, and filament continuity. Will test all tube types normally encountered in radio and TV service work. Sockets provided for 4, 5, 6, and 7-pin large, rectangular, and miniature types, octal and loctal types, the Hytron 9-pin miniatures, and pilot lamps. Condition of tubes indicated on a large 442” meter with multi-color “good-bad” scale. An illuminated roll chart is built right in, providing test data for various tube types. This tester provides switch selection of 14 different filament voltage values from 0.75 volts to 117 volts. Individual switches control each tube element. Close tolerance resistors employed in critical test circuits for maximum accuracy. A professional instrument both in appearance and performance.
The Model TC-2 is very simple to build, even for a beginner. It employs a color-coded cable harness for neat, professional under-chassis wiring. Comes with at- tractive counter style cabinet, and portable cabinet is available separately. At this price, even the part-time serviceman can afford his own tube checker for maxi- mum efficiency in service work.
HEATHKIT TV PICTURE TUBE
TEST ADAPTER
Designed especially for use with the Model
TC-2 tube checker. Use it to test TV picture MODEL 355 tubes for emission, shorts, etc. Consists of 5 50 12-pin TV tube socket, 4 ft. cable, octal 4 ° connector, and necessary technical data. Shpg. Wt. Not a kit. 1 Lb.
peecceccoesceee pe CCC OO CEC OOOO OOOO OOOO OEEES®
HEATHKIT PORTABLE : > ‘ HEATHKIT VISUAL-AURAL SIGNAL TRACER KIT : Although designed primarily for radio receiver work, this valuable instrument finds extensive application in FM and TV servicing as well. Features a high-gain channel with de- modulator probe, and a low-gain channel with audio probe. Will trace signals in all sections of a radio receiver and in many sections of a FM set or TV receiver. Uses built-in
speaker and electron beam eye tube for in- dication. Also features built-in wattmeter | MODEL T-3 and a noise locater circuit. Provision for $9350 patching speaker and/or output transformer a into external set. Shpg. Wt. 9 Lbs.
»
HEATHKIT CONDENSER CHECKER KIT
The Model C-3 consists of an AC powered bridge for both capacitive and resistive measurements. Bridge balance is in- dicated on electron beam eye tube, and capacity or resistance value is indicated on front panel calibrations. Measures capacity in four ranges from .00001 mfd to .005 mfd, .001 mfd to .5 mfd, .1 mfd to 50 mfd, and 20 mfd to 1000 mfd. Measures resistance in two ranges, from 100 ohms to 50,000 ohms, and from 10,000 ohms to 5 megohms. Selection of five different polarizing voltages for check-
ing capacitors, from 25 volts DC to 450 MODEL C-3 volts DC. Checks paper, mica, ceramic, g 50 and electrolytic capacitors. Indicates power 19 © factor of electrolytic condensers. Shpg. Wt. 7 Lbs.
RADIO & TELEVISION NEWS
PIONEER DESiGn . a
New i a ” unique °PProaches to inst *signs are’ gq Heath Co
design features,
HEATHKIT- Impedance Bridge Kit
sk %% precision resistors and silver-mica capacitors.
oe Battery-type tubes, no warm-up required.
* Built-in phase shift generator and amplifier.
The Model IB-2 is a completely self-contained unit. It has a built-in power supply, a built-in 1000 cycle generator, and a built-in vacuum tube detector. Provision has been made on the panel for connection to an external detector, an external signal generator, or an external power supply. A 100-0-100 micro- ampere meter on the front panel provides for null indications. Measures resistance from 0.1 ohm to 10 megohms, capacitance from 10 mmf to 100 mfd, inductance from 10 mh to 100 h, dissipation factor (D) from 0.002 to 1, and storage factor (Q) from 0.1 to 1000. % of 1% decade resistors employed
for maximum accuracy. Typical accuracy figures are:
resistance, +3T; capacitance +3%; inductance, +10%; dissipation factor, +20%; storage factor, +20%. Employs a Wheatstone bridge, a Capacity Comparison bridge,
MODEL
a Maxwell bridge, and a Hay bridge. Special two-section CRL dial provides IB-2
maximum convenience in operation. Use the Model IB-2 for determining values of unmarked components, checking production or design samples, etc.
A real professional instrument.
>
HEATHKIT “Q’” METER KIT
The Q Meter permits measurement of inductance from 1 micro- henry to 10 millihenries, ““Q”’ on a scale calibrated up to 250 full scale, with multiplying factors of 1 or 2, and capacitance from 40 mmf to 450 mmf, +3 mmf. Built-in variable oscillator per- mits testing components from 150 kc to 18 mc. Large 414” panel- mounted meter is features. Very handy for checking peaking coils, chokes, etc. Use to determine values of
unknown condensers, both variable and fixed. MODEL QM-1 Compile data for coil winding purposes, or $4450 measure RF resistance. Distributed capacity, « and Q of coils. Shpg. Wt. 14 Lbs.
HEATHKIT 6-12 VOLT BATTERY ELIMINATOR KIT
This completely modern battery eliminator will supply DC out- put in two ranges for both 6-volt and 12-volt automobile radios. The output is variable for each range, so that operating voltage can be raised or lowered to determine how the receiver functions under adverse conditions. Range is 0-8 volts DC or 0-16 voits DC. Will supply up to 15 amperes on the 6-volt range, or up to 7 amperes on the 12-volt range. Two 10,000 microfarad output filter capacitors insure smooth DC output. Two
separate panel meters indicate output voltage MODEL BE-4 or output current. Makes it possible to test $3]5° automobile radios inside at the workbench. bd Will also double as a battery charger. Shpg. Wt. 17 Lbs.
January, 1957
5 50 Shpg. Wt e 12 Lbs.
HEATHKIT ISOLATION TRANSFORMER KIT
This device isolates equipment under test from the power line. It is rated at 100 volt-amperes continously, or 200 volt-amperes intermittently. AC-DC sets may be plugged directly into the IT-1 without the chassis becoming “‘hot.’’ Additionally, since the IT-1 is fused, it is ideal for use as a buffer between the power line and a questionable receiver, or a new piece of equipment. Protects main fuses. Features voltage control, allowing control of the output from 90 volts to 130 volts. MODEL IT-1 Panel meter monitors output voltage. A very $165° handy device at an extremely low price. e Shpg. Wt. 9 Lbs.
HEATHKIT 6-VOLT VIBRATOR TESTER KIT This instrument functions very much like a tube checker, to test auto radio vibrators. Vibrator condition is indicated on a simple “good-bad” scale. Tests for proper starting and overall quality of operation, of both interrupter and self-rectifier types of 6-volt vibrators. The model VT-1 is designed to operate from any bat- tery eliminator capable of delivering continuously variable out- put from 4 to 6 volts DC at 4 amperes or more. It is an ideal companion unit for the Heathkit Model BE-4 battery eliminator. The construction book for MODEL VT-1 the VT-1 contains vibrator test chart for popu- $1450 lar 6-volt vibrator types. A real time saver! ° Shpg. Wt. 6 Lbs.
Transmitter Kit
The Heathkit DX-100 transmitter is in a class by itself in that if offers features far beyond those normally received at this price level. It takes very little listening on the bands to discover how many of these transmitters are in opera- tion today. A truly amazing piece of amateur gear. The DX-100 features a built-in VFO and a built-in modulator. It is TVI suppressed, 2nd uses pi network interstage coup- ling and output coupling. Will match antenna impedances from approximately 50 to 600 ohms. Extensive shielding is employed, and all incoming and outgoing circuits are filtered. The cabinet features interlocking seams for sim- plified assembly and minimum RF radiation outside of the cabinet. Provides a clean strong signal on either phone or CW, with RF output in excess of 100 watts on phone, and 120 watts on CW. Completely bandswitching from 160 through 10 meters. A pair of 1625 tubes are used in push-pull for the modulator, and the final consists of a pair of 6146 tubes in parallel. The VFO dial and meter face are illuminated, and all front panel controls are located for maximum convenience. Pax:1 meter reads driver plate I, final grid I, final plate I, final plate voltage, and modulator current. The chassis is constructed of heavy #16 gauge copper-plated steel. Other high-quality com- ponents include potted transformers, ceramic switch and variable capacitor insulation, silver-plated or solid-silver switch terminals, etc. All coils are pre-wound, and the main wiring cable is pre-harnessed. The kit can be built by a beginner from the comprehensive step-by-step in- structions supplied. It is a proven, trouble-free rig, that will insure many hours of “on-the-air” enjoyment in your ham shack.
Fe SSSSSSESSSEOSSSEEEOOSESESESE HEATHKIT VFO KIT
You can go VFO for less than you might expect. Here is a variable frequency oscillator that covers 160, 80, 40, 20, 15, 11, and 10 meters with three basic oscillator frequencies, that sells for less than $20. Provides better than 10 volt average RF output on fundamentals. Plenty of drive for most modern transmitters. Requires a power source of only
250 VDC at 15 to 20 ma. and 6.3 VAC at MODEL VF-1 0.45A. Incorporates a regulator tube for
stability. Illuminated frequency dial reads fre- $1950 quency directly on the band being employed. Temperature-compensated capacitors offset coil heating.
Shpg. Wt. 7 Lbs.
NEW HEATHKIT CW TRANSMITTER KIT
The brand new Heathkit Model DX-20 Transmitter is one of the most efficient little rigs available today. Featuring an entirely new circuit, it is ideal for the novice, and even for the advanced-class CW operator. A 6DQ6A final amplifier provides plate power input of 50 watts. A 6CL6 oscillator is employed, and a 5U4GB rectifier. The transmitter features one-knob bandswitching to cover 80, 40, 20, 15, 11 and 10 meters. It is designed for crystal excitation, but may be excited by an — VFO. A
i network output circuit matches antenna > impedances between 50 and 1000 ohms. MODEL DX-20 Front panel controls are functionally located C4 for your convenience. If you appreciate a 5 good signal on the CW bands, this is the transmitter for you! Shpg. Wt. 18 Ibs.
RADIO & TELEVISION NEWS
HEATHKIT PHONE AND CW Transmitter Kit
%& 6146 final amplifier for full 65-watt plate power input.
are % Phone and CW operation on 80, 40, 20, 15, 11, ment, | |
play and 10 meters. Pi network output coupling,
© so-called
's a big difference,
n. Power and factory.
can offer top-quql components, at sy. SS Opposed to jh
! eco say, there Pte
. Needless to Switch selection of three crystals — provision for
external VFO excitation.
The DX-35 features a 6146 final amplifier to provide 65 watts plate power input on CW, with controlled carrier modulation peaks up to 50 watts on phone. In addi- tion, it is a most attractive transmitter. Modulator and power supplies are built-in, and the rig covers 80, 40, 20, 15, 11, and 10 meters with a single band-change switch. Pi network output coupling provided for matching various antenna im- pedances. A 12BY7 buffer stage provided ahead of the final amplifier for plenty of drive on all bands. 12BY7 oscillator and 12AU7 modulator. Provision for switch selection of three different crystals. Crystals reached through access door at rear. Front panel controls marked “off—CW-—stand-by—phone”, “final tuning”, “antenna coupling”, “drive level control”, and “band change switch”. Panel meter indicates final grid current or final plate current. A perfect low-power transmitter both for the novice, and for the more experienced operator. A remarkable power package for the price. Incidentally, the price includes tubes, and all other components neces- sary for assembly. As with all Heathkits, comprehensive instruction manual assures successful assembly. :
MODEL DX-35
$ QS Sheg. wr. € 24 Lbs.
HEATHKIT “GQ” MULTIPLIER KIT
The QF-1 functions with any receiver with an IF frequency between 450 and 460 ke that is not AC-DC type. Operates from: the receiver power supply, requiring only 6.3 VAC at 300 ma. and 150 to 250 VDC at 2 ma. Simple to connect with cable and plugs supplied. Provides additional selectivity for Separating two signals, or will reject one sig-
nal and eliminate heterodyne. A big help on q crowded bands. Provides an effective Q of WOBR O81 approximately 4,000 for sharp “‘peak”’ or $995 “null”. Tunes to any signal within the IF bandpass of the receiver, without changing shoo. we. 3 Lbs. main receiver tuning dial.
HEATHKIT ANTENNA IMPEDANCE METER KIT
This instrument employs a 100 microampere panel meter and covers the impedance range of 0-600 ohms for RF tests. Func- tions up to 150 mc. Used in conjunction with signal source, such as the Heathkit Model GD-1B grid dip meter, the Model AM-1 will determine antenna resistance and
resonance, match transmission lines for mini- MODEL AM-1 mum standing wave ratio, determine receiver
input impedance, etc. Will also double as a $1450 phone monitor. A very valuable device for
many uses in the ham shack. Shpg. Wi. 2 the.
HEATHKIT ANTENNA COUPLER KIT
This device is desizned to match the Model AT-1 transmitter to a long-wire antenna. In addition to impedance matching, this unit incorporates an L-type filter which attenuates signals above 36 megacycles, thereby reducing TVI. Designed for 52 ohm coaxial input. Handles power up to 75 watts, 10 through 80 meters. Uses a tapped inductor and vari-
able capacitor. Neon RF indicator on front MODEL AC-1 panel. Copper-plated chassis—high quality
components throughout—simple to build. $1450 Eliminates waste of valuable communications - power due to improper matching. A “‘natu- Shpg. Wt. 4 Lbs. ral” for all AT-1 transmitter owners.
January, 1957
HEATHKIT GRID DIP METER KIT
The grid dip meter was originally designed for the ham shack. However, its use has been extended into the service shop and laboratory. Continuous frequency coverage from 2 mc to 250 me with pre-wound coils. 500 microampere panel meter em- ployed for indication. Use for locating parasitics, neutralizing, determining RF circuit resonant frequencies,
etc. Coils are included with kit, as is a coil MopEL GD-1B rack. Front panel controls include sensitivity
control for meter, and phone jack for listen- $1995 ing to zero-beat. Will also double as an ab- °
sorbtion-type wavemeter. Shpg. Wt. 4 Lbs.
eg
MODEL BR-2 18”
(Less Cabinet eames §8INCLUDING NEW EXCISE TAX#.
This kit is an ideal “first project” a Higehkit talors, Aone ee ee ee
Miniat a St tach PR speaker.
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This sensitive and reliable instrument has already found ex and 2 medical and industrial laboratories. It offers
reasonable price. Front-panel ‘meter i and oral indication :
% Stable circuit requires apes one 673 +» and two 1¥2 volt “A” batteries, _
HEATH COMPANY A Subsidiary of Daystrom, Inc. a BENTON HARBOR 15, MICH.
if you have never built
Receiver Kit
You need no previous experience in electronics to build this table-model radio. The Model BR-2 receiver covers 550 ke to 1620 ke and features good sensitivity and selec- tivity over the entire band. A 5%” PM speaker is em- ployed, along with high gain miniature tubes and a new rod-type built-in antenna. Provision has been made in the design of this receiver for its use as a phonograph ampli- fier. The phono jack is located on the back chassis apron. A transformer operated power supply is featured for safety of operation, as opposed to the usual AC-DC supply commonly found in “economy radio kits.” Don’t let the low Heathkit price deceive you. This is the kind of set you will want to show off to your family and friends after you have finished building it.
Construction of this radio kit is very simple. Giant size
pictorial diagrams and detailed step-by-step instructions assure your success. The construction manual also includes an explanation of basic receiver circuit theory so you can “learn by doing” as the receiver is built. The manual even provides information on resistor and capacitor color codes, soldering techniques, use of tools, etc. If you have ever had the urge to build your own radio receiver, the out- standing features of this popular Heathkit deserve your attention. CABINET: Proxylin impregnated fabric covered plywood cabinet available for the BR-2 receiver as shown. Complete with alumi- num panel, reinforced speaker grill, and protective rubber feet. Shipping weight 5 Ibs., part No. 91-9A
HEATHKIT CRYSTAL RECEIVER KIT
The crystal radio of Dad’s day is back again, but with big improvements! The Model CR-1 employs a sealed germanium diode, eliminating the critical “‘cat’s whisker’’ adjustment. It is housed in a compact plastic box, and features two Hi-Q tank circuits, employing ferrite core coils and variable air tuning capacitors. The CR-1 covers the standard broadcast band from 540 ke to 1600 kc, and no external power is MODEL CR-1 required for operation. Could prove valuable
for emergency signal reception, This easy-to- $7795 build kit is a real “learn by doing experience mecadoine NEW for the beginner, and makes an interesting EXCISE TAX $ project for all ages. Shpg. Wt. 3 Lbs.
~]
-
HEATHKIT ENLARGER TIMER KIT
The Model ET-1 is an easy-to-build device for use by amateur or professional photographers in controlling the timing cycle of an enlarger. It covers the range of 0 to 1 minute with a con- tinuously variable, clearly calibrated scale. The timing period is pre-set, and the timing cycle is initiated by depressing the spring-return switch to the “print’’ position. Front panel pro- vision is made for plugging in the enlarger and a safelight. The safelight is automatically turned ‘‘on”’ when the enlarger is “off”. Handles up to 350 watts. The timing cycle is controlled elec- MODEL ET-1 tronically for maximum accuracy and relia- $]]5° bility. Very simple to build in only one ° evening, even by a beginner. Shpg. Wt. 3 Lbs.
RADIO & TELEVISION NEWS
ere 85 he be ee ee es
HEATHKIT HIGH FIDELITY
Preamplifier Kit
5 switch-selected inputs, each with its own level control.
COMPREHENSIVE INSTRUCTIONS
Th
cana ee assembly instructio
Pee Gre the finest availabi .
Segins at the beginning eben, ’
Equalization for LP, RIAA, AES, and Early 78's.
Separate bass and treble tone controls, and special hum control.
Clean, modern lines and satin-gold enamel finish.
Literally thousands of these preamplifiers are in use today, because the kit meets
or exceeds specifications for the most rigorous high-fidelity applications, and
will do justice to the finest available program sources. Provides a total of 5
inputs, each with individual level controls (three high-level and two low-level).
Frequency response is within 1 DB from 25 CPS to 30,000 CPS, or within
1% DB from 15 CPS to 35,000 CPS. Hum and noise are extremely low, with
special balance control for absolute minimum hum level. Tone control pro-
vides 18 DB boost and 12 DB cut at 50 CPS, and 15 DB boost and 20 DB
cut at 15,000 CPS. Cabinet measures only 12-9/16” W. x 3%” H. x 4%” D,
and it is finished in beautiful satin-gold enamel. 4-position turnover and 4 MODEL position roll-off controls provide “LP,” “RIAA,” “AES,” and “early 78” equal- WA-P2 ization, and 8, 12, 16, and 1 flat position for roll-off. Derives operating power
from the main amplifier, requiring only 6.3 VAC at 1 ampere and 300 VDC
at 10 MA. Easy to construct from step-by-step instructions and pictorial dia-
grams provided.
(With Cabinet) Shpg. Wt. 7 Lbs,
19
e@eeeeeeoeeooooooooooeoeeeeeeaeeeeaeaeee ee eee e eee eeeeee ee eee e@ HEATHKIT HIGH FIDELITY FM TUNER KIT IF circuits, and better than 10 UV sensitivity for 20 DB of
the mixer to increase overall gain and reduce oscillator leak-
ieting. A high gain, cascaded, RF lifier is used ahead of v Illuminated slide-rule dial covers 88 to 108 MC. pagar + ads emake y st sadieanin eaaiiciass tales
% Modern circuit emphasizes sensitivity and
stability,
% Housed in attractive satin-gold cabinet to match WA-P2 and BC-1,
This amazing new FM tuner can provide you with real high- fidelity performance at an unbelievably low price level. Cover- ing 88 to 108 MC, the modern circuit features a stabilized, temperature-compensated, oscillator, A.G.C., broadbanded
HEATHKIT BROADBAND AM TUNER KIT
This AM tuner has been designed especially for high-fidelity applications. It incorporates a low-distortion detector, a broadband IF, and other features essential to usefulness in high-fidelity. Special voltage-doubler detector employs crystal diodes for low distortion. Sensitivity and selectivity are excel- lent. Audio response is + 1 DB from 20 CPS to 2 kc, with 5 DB of pre-emphasis at 10 kc to compensate for station roll-off. Covers the standard broadcast band from MopEl BC-1 550 to 1600 kc. Incorporates a 10 kc whistle- filter and re a 6 DB signal-to-noise $2595 ratio at 2.5 UV. RF and IF coils are pre- td aligned, and power supply is built-in. Incor- pp eked porates AVC, two outputs, and two antenna = pws, Cobinet) inputs. Shpg. Wt. 8 Lbs.
January, 1957
age. It employs a ratio detector for high efficiency without sacrifice in high-fidelity performance. IF and ratio transformers are pre-aligned, as is the front end tuning unit. This means the kit can be constructed by a beginner, without elaborate test and alignment equipment. The FM-3A is designed to match the WA-P2 preamplifier and the BC-1 AM MODEL FM-3A tuner. An illuminated slide-rule dial is em- $2595 ployed for frequency indication. Step-by-step instructions and large pictorial diagrams yy gl Sree Snore. (With Cabinet) Shpg. Wt. 7 Lbs,
HEATHKIT ELECTRONIC CROSS-OVER KIT
This unusual device functions to separate low frequencies and high frequencies so that they may be fed to separate amplifiers and to separate speakers. This eliminates the need for conven- tional cross-over circuits, since the Model XO-1 does the com- plete job electronically. Cross-over frequencies of 100, 200, , 700, 1,200, 2,000 and 3,500 CPS are selectable with front panel controls on the XO-1, and a separate level control is provided for each channel. Minimizes tnter- modulation distortion problems. Handlesun- MODEL XO-1 limited power, since frequency division is accomplished ahead of the power stage. $1895 Attenuation is 12 DB per octave, with sharp °
“knee” at cut-off frequency. Shpg. Wt. 6 Lbs.
HIGH FIDELITY
Amplifier Kit
This 25 watt unit is our finest high-fidelity amplifier. Using a special design peerless output transformer, and KT-66 output tubes by Genalex, the Model W-5M provides per- formance characteristics unsurpassed at this price level. Frequency response is + 1 DB from 5 to 160,000 CPS at 1 watt. Harmonic distortion is less than 1% at 25 watts and 1M distortion is less than 1% at 20 watts (60 and 3,000 CPS, 4 to 1). Hum and noise are 99 DB below 25 watts. Damping factor is 40 to 1. Input voltage for 5 watts output is 1 volt. Tubes employed are a pair of 12AU7’s, a pair of KT-66’s and a 5R4GY rectifier. Measures 13-3/32” W. x 8%” D. x 8%” H. Output im- pedance is 4, 8, or 16 ohms. Featured, also, is the “tweeter saver” which suppresses high frequency oscillation, and a new type balancing circuit requiring only a voltmeter for indication. This balance is easier to adjust, and results in a closer “dynamic” balance between output tubes. The Model W-5M provides improved phase shift character- istics, reduced IM and harmonic distortion, and improved frequency response. Conservatively rated high-quality com- ponents are used throughout to insure years of trouble-free operation. No technical background or training is required for assembly. Step-by-step instructions are provided for every stage of construction, and large pictorial diagrams illustrate exactly where each wire and component is to be placed. An amplifier for music lovers who can appreciate subtle differences in performance. Just. ask the audiofile who owns one!
HEATHKIT SINGLE CHASSIS—WILLIAMSON TYPE HIGH FIDELITY AMPLIFIER KIT
The 20-watt Model W-4AM Williamson type amplifier is a tremendous high-fidelity bargain. Combining the power sup- ply and main amplifier on one chassis, and using a special- design output transformer by Chicago Standard brings you savings without a sacrifice in quality. Employing 5881 output tubes, the frequency response of the W-4AM is + | DB from 10 CPS to 100 ke at 1 watt. Harmonic distortion is only 1.5% at 20 watts. Output impedance is 4, 8, or 16 ohms. Hum and noise are 95 DB below 20 watts.
MODEL W-4AM: Shpg. Wt. 28 Lbs. Express only.......$39.75 MODEL W-4A: Consists of Model W-4AM plus Model WA-P2 pre- amplifier. Shpg. Wt. 35 Lbs. Express only............-- $59.50
<<
HEATHKIT 20-WATT HIGH FIDELITY AMPLIFIER KIT
This high-fidelity amplifier features full 20-watt output using
ush pull 6L6 tubes. Built-in preamplifier provides 4 separate inputs, selected by a panel-mounted switch. It has separate bass and treble tone controls, each offering 15 DB boost and cut. Output transformer is tapped at 4, 8, 16, and 500 ohms. Designed primarily for home installations, but also used ex- tensively for public address applications. True MODEL A-98 high-fidelity performance with frequency re-
nse of + 1 DB from 20 CPS to 20,000 CPS. $35°°
Total harmonic distortion only 1% (at 3 DB e below rated output). Shpg. Wt. 23 Lbs.
RADIO & TELEVISION NEWS
Sroecasi2o0oc2w"s> saa
HEATHKIT HIGH FIDELITY
Range Extending
SPEAKER SYSTEM KIT
*%
a Easy-to-assemble cabinet of furniture-grade plywood.
%
rg os with q ax —— and some ‘gman . in kit form, Since t ix , 5, we have Prices. This nop increasing our including this ne
+ include an appli hx
High quality speakers of special design — 15” woofer and compression-type super-tweeter.
Attractively styled to fit into any living room.
on some kits ‘ Matches Model SS-1.
W tax in them, Thank you,
HEATH COMPANy
but merely
This range extending unit is designed especially for use with the Model SS-1 speaker system. It consists of a 15” woofer, providing output between 35 and 600 CPS, and a compression-type super-tweeter that provides output between 4,000 and 16,000 CPS. Cross-over frequencies are 600, 1,600, and 4,000 CPS. The SS-1 provides the mid-range, and the SS-1B extends the coverage at both ends of the spectrum. Together, the two speaker systems provide output from 35 to 16,000 CPS within + 5 DB. This easy-to-assemble speaker enclosure kit is made of top-quality furniture-grade plywood. All parts are pre-cut and pre-drilled, ready for assembly and the finish of your choice. Complete step-by-step instructions are provided for quick assembly by one not necessarily experienced in woodworking. Coils and capacitors for proper cross-over network are included, as is a balance control for super-tweeter output level. The SS-1 and SS-1B can provide you with unbelievably rich audio reproduction, and yet these units are priced reasonably. The SS-1B measures 29” H. x 23” W. x 17%" D. The speakers are both special-design Jensens, and the power rating is 35 watts. Impedance is 16 ohms.
MODEL SS-1B
95 Shpg. Wt. 80 Lbs.
SSOSSHSSHSHSSSSSOSOSSSSSSSSSSSSEOSESOSSSOSHSEHSSEOSESEHEEHEHSEESEEEEEO
HEATHKIT HIGH FIDELITY SPEAKER SYSTEM KIT
This speaker system is a fine reproducer in its own right, covering 50 to 12,000 CPS within + 5 DB. However, the story does not end there. Should you desire to expand the system later, the SS-1 is designed to work with the SS-1B range extending ynit — providing additional frequency coverage at both ends of the spectrum. It can fulfill your present needs, and still provide for the future. The SS-1 uses two Jensen speakers; an 8” midrange-woofer, and a compression- type tweeter. Cross-over frequency is 1,600 CPS, and the system is rated at 25 watts. Nominal impedance is 16 ohms. The cabinet is a ducted-port bass-reflex type. Attractively styled, the Model SS-1
MODEL SS-1
$39”
Shpg. Wt. 30 Lbs.
Special design ducted-port, bass-reflex enclo- sure.
Two separate speakers for high and low fre- quencies.
Kit includes all parts and complete instructions
* *
features a broad “picture-frame” molding that will blend with any room decorating scheme. Pre-cut and pre-drilled wood parts are of furniture grade plywood. The kit is easy-to-build, and all component parts are included, along with complete step-by-step instructions for assembly. Can be built in just one evening, and will provide you with
*
for assembly. many years of listening enjoyment thereafter.
‘ORDER iBLANK
NOTE: All prices subject te change without notice.
SHIP VIA DD Parcel Post (C) Express
CO Freight
C) Best Way
Name
Address
State (PLEASE PRINT)
City & Zone Enclosed find ( ) check ( ) money order for__. Please ship C.0.0. ( ) postage enclosed for___—____ pounds. On Express orders do not in- clude transportation charges — they will be collected by the express agency at time of delivery.
ON PARCEL POST ORDERS in- clude postage for sant shown. ORDERS FROM CANADA and APO’S must include full remit-
PRICE
| MODEL NO.
QUANTITY ITEM
January, 1957 93
FINEST QUALITY | STEEL SHANK |} AND SLEEVE
co BRIGHT PLATED FINISH °
ST PLASTIC HANDLE ens
Ny PRESENTING THE
PINTITE °
WRENCHES
WITH THE EASY "FINGER-CONTROL”
GRIP ano RELEASE ACTION
FOR THOSE
RONG L cee ET-AT PLACES -
SIZES — Puls SLEEVE TO sauante
¥u" TO Ye"
ONE HAND OPERATION—
© GRIPS nuts or bolts of any material @ HOLDS firmly in any position
@ TIGHTENS nut or bolt securely
@ RELEASES at the pull of the fingers’
Write for catalogue
STEVENS WALDEN Inc.
450 SHREWSBURY STREET — WORCESTER, MASSACHUSETTS
MAKERS OF WORLD-FAMOUS HAND TOOLS FOR OVER 50 YEARS
CUT CHASSIS HOLES FAST!
Smooth, accurate openings made in 1% minutes or less with Greenlee Radio Chassis Punch
Save hours of tedious work. Sagen make smooth, accurate holes in meta
bakelite, or hard rubber with a GreeNLEE Chassis Punch. Easy to operate . . . simp!
turn with an ordinary — Round, square, key, and “‘D” types . . . wide range of sizes to make openings for sockets, plugs, controls, meters, terminal strips, transformers, panel lights, etc. Assure perfect fit of parts and professional finish to every job. Write for descriptive liter- =, _ ature.GreenleeTool GREENLEE Co., 1881 Columbia ~~
Ave., Rockford, Ill.
gy “
PREPARES YOU FOR YOUR LICENSE EXAMINATION!
® Questions on Basic Law ¢ Basic Operating Practice * Basic Radiotelephone
© Advance Radiotelephone
Now, in one convenient volume, complete study-guide questions with clear, concise answers for preparation for all USA commercial radio-telephone operator's li- cense examinations.
Paperbound
$3.7
BUY poe YOUR DISTRIBUTOR
Add
EDITORS and ENGINEERS, Ltd. Summerland 2, California
in U.S.A. (plus sales tax where applicable)
What's Ahead for the TV Industry
Dr. W. R. G. Baker takes optimistic view, expects growth, but also change.
N HIS report to the fall meeting of
the Institute of Radio Engineers and the Radio-Electronics-Television Man- ufacturers Association, Dr. W. R. G. Baker, president of RETMA and vice- president of the General Electric Com- pany, anticipated a bright future for all facets of the TV industry. He accompanied his predictions with the observation that many forecasts for the electronics industry made in re- cent years turned out to be not optimistic enough.
Since Dr. Baker was unable to ap- pear in person, his report was delivered by Arthur V. Loughren, president of IRE. Some of the highlights, statistical and non-statistical, included the fol- lowing “guesstimates”’ :
As compared to about 7% million TV sets being sold annually now, about 10 million a year will be the annual sale by 1960.
Closed-circuit industrial TV _ will quadruple over the next four years, with sales, now at the $6 million mark,
| reaching $24 million by 1960.
With the rapid development of
| scatter transmission techniques, trans-
oceanic TV broadcasts are only a matter of time.
With many other nations throughout the world ready to begin TV broad- casting for the first time in 1957, the sales potential for foreign markets will continue to forge upward.
Truly portable transistorized TV sets will be on the market within two years.
Color TV will always cost more than monochrome receivers, and there will surely be no drastic downward revi- sion of color prices in the immediate future, although eventually less ex- pensive color sets are in the offing.
Looking into the immediate future, 1956 will end up as one of the best years for TV receiver sales despite
| the slackening off that characterized the first 9 months.
On the u.h.f.-v.h.f. dispute, Dr. Bak- er advised a go-slow attitude until a
thorough study has been made.
Stating that there has been no precedent in industrial history for the growth of electronics, Dr. Baker pointed out, “Ten years ago it was an industrial infant and now it pro- vides employment for one-and-three- quarter million Americans, which rep- resents one person in every 40 in our total work force. And the amazing thing is that 75 per-cent of these jobs didn’t exist just 10 years ago.” -§Q-
RADIO & TELEVISION NEWS
Here’s how to GET MORE WORK OUT OF YOUR
Oscilloscope!
Keep your Jackson tube checker up-to-date with
this information on testing recent tube types.
JACKSON MODEL 648
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ery " ilemant Circuit
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8BA8 A Complete, easily understood guide to using the handiest service instrument of them all MODERN OSCILLOSCOPES AND THEIR USES By Jacob H. Ruiter, Jr. Oscilloscopes are gold
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SCOPES ARE “GOLD MINES” When You Learn to Use Them Right!
Each operation is explained step by step. You learn to determine just where and how to use the *scope on specific jobs; how to make connections and adjust circuit components; how to set the controls; and HOW TO ANALYZE OSCILLOSCOPE PAT- TERNS fast and accu 5
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*When testi z this section 5 fies shorts, the K (Cathode) and G1 (Grid no. 1) positions of the shorts
test switch will be reversed.
January, 1957
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ALLIED RADIO 100 N. Western Ave., Chicago 80, IIt,
Mac's Service Shop (Continued from page 76)
bellow like a bull into the mike with- out the least sign of an are or without popping a fuse.”
“Well, I’m certainly glad you found your trouble,” Mac remarked as he hung up his street coat and shrugged his way into his shop coat. “Now how’s about helping me with mine? Listen to how badly this cussed record player distorts. It has a lot of years on it, but it still should sound a lot better than that.”
He turned on the straight 78 rpm record player, and the music that is- sued from the speaker made Barney wince.
“Sounds like a bad needle,” he sug- gested as he picked up the tone arm from the record.
“That was my thought, too; so I put in a brand new needle. If anything that made it worse. Then I decided it must be the cartridge, but a new one did not make a particle of difference. Finally I went over the amplifier with a fine-toothed comb, changing tubes, checking voltages, looking for leaky capacitors, etc.; but there is absolutely nothing wrong with that record player except that it sounds horrible!”
While Mac was talking, Barney had been carefully scrutinizing the needle with the tone arm practically rubbing his pug nose. Finally he removed the needle from the chuck and took it over to the bench light for an even closer inspection. Next, without saying a word, he got a new needle from a dis- play card and installed it in the tone arm. When the arm was lowered to the still-spinning record, the music came forth clear and undistorted.
“Well I’ll be darned!” Mac ex-
claimed. “I know I changed that nee- dle. The new one must have been bad right from the start.”
“Is that so hard to believe?” Barney wanted to know. “You recall that ev- ery now and then we find a defective new tube, a leaky new capacitor, or a new resistor that is not of the value indicated on it. It’s true this happens very, very rarely; but it still happens. Why couldn’t a phonograph needle slip through inspection once in a blue moon? Obviously this one did, for it has a point on it like a postoffice pen.”
“Well, Irish, that’s one time you certainly showed up the old man,” Mac said ruefully.
“Aw, don’t take it so hard,” Barney consoled; “it was just my younger eyes that allowed me to spot the trouble.”
“Nope, I’m not going to beg off on that excuse,” Mac said firmly. “In the first place, I'll not admit I can’t see just as well as you can. In the second place, I was guilty of. doing something I’ve bawled you out for a dozen times: disregarding the obvious symptom. That sounded exactly like a bad needle right from the start, but after I put in a new needle and it sounded worse
-and that should have tipped me off at once—I dismissed the needle possi- bility from my mind entirely and went looking for something else. I was just plain stupid, and I’ll not deny it—or let you deny it.”
“Okay! Okay! Have it your own way,” Barney said agreeably; “but I’ll wager if all the time service techni- cians have wasted because they failed to suspect a new component could be placed end-to-end, it would add up to a light-year or so.”
“Which is about the same length of time it would take to straighten out that mixed metaphor,” Mac remarked as he picked up his solder gun. —30-
An extensive program is under way at Bell Telephone Laboratories to develop travel- ing-wave amplifier tubes for communications applications. Here tests are being conducted on an experimental tube designed to provide 5 watts output with a band-
width of 500 mc. in the 6000 mc. band.
In this particular test, designed to de-
tect and measure a certain type of nonlinearity in the tube, a 6000 mc. amplitude- modulated signal is fed to the traveling-wave tube. If nonlinearity exists, some of this amplitude modulation will be converted to phase modulation, which can then be detected in the amplified signal at the output of the traveling-wave tube. Note the very extensive use of elaborate r.f. plumbing in the test setup shown.
Be *,
RADIO & TELEVISION NEWS
SS 9 ) Manufacturers’ EUAN Literature
CAPACITOR REPLACEMENTS
Cornell-Dubilier Electric Corporation of South Plainfield, N. J. has an- nounced publication of its annual Re- placement Capacitor Catalogue.
Prepared especially for distributors, Catalogue 200D-3, covers electrolytic, paper tubular, industrial, mica, ceram- ic, filter, and motor starting units. The 44-page, 3-color catalogue is sectional- ized and thumb-indexed for quick ref- erence.
Copies of the new catalogue will be supplied by the company’s distributors or upon letterhead request direct to the manufacturer.
METAL BOX LINE
Zero Manufacturing Company, 1121 Chestnut Street, Burbank, Cal. has is- sued an elaborate 60-page catalogue which describes its line of deep-drawn and fabricated cases of aluminum, brass, and steel.
Included are special cases designed especially for electronic and instru- ment applications. The company stocks
some 1400 standard items while cus- |
tom sizes are available on special order.
Manufacturers are invited to write for a copy of this catalogue.
TRANSISTOR SPECIFICATIONS
General Transistor Corp., 130-11 90th Ave., Richmond Hill 18, N. Y. has issued a tentative specification and cross reference sheet on its line of her- metically sealed germanium p-n-p al- loyed junction transistors.
Technical bulletin No. G-7 lists types, uses, maximum ratings, charac- teristics, and comparable reference types as manufactured by Raytheon, G-E, Sylvania, RCA, CBS, Texas In- struments, and Philco.
The company will supply a copy of this handy wall chart on request.
CAPACITOR CATALOGUE
Cornell-Dubilier Electric Corpora- tion, South Plainfield, N. J. has issued a colorful 20-page brochure describing its line of “Tiny Mike” ceramic ca- pacitors.
Catalogue No. 616 includes complete physical and electrical characteristics, photographs of the capacitors, and graphs of capacitance variation with temperature changes.
Write the manufacturer direct for a copy of this catalogue.
ASSOCIATION ENCYCLOPEDIA Gale Research Company, 424 Book Tower, Detroit 26, Mich., has an- nounced the publication of its “Ency- clopedia of American Associations” which lists more than 5000 associa-
January, 1957
H red by a >
NeW cece Just what you asked for!
¢ Hilo Model 505 — Channels 2-83
The spiral antenna that is designed for maxi- mum performance featuring the NEW TELE- versatile antenna swivels on ball and socket in any direction.
SCOPING DIPOLES. This
Gold spirals, plastic base blend with any room.
New eee
For every TV
owner
Hilo Model 404 Channels — 2-83.
NEW INDOOR ANTENNA that swivels with a gentle touch of your little finger. Dipoles swivel on ball and socket in every direction. Golden spirals and decorative plastic base blend with all furniture. RECEPTION IS GUARAN- TEED. LIST... . $12.95
LIST... . $14.95
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INSIST ON THE GENUINE Hi-Lo Sx
Known and accepted «
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GUARANTEED PERFORMANCE
Hil Model 101 — Channels 2-13. t Othe original and world famous antenna that is wanted, demanded and used for GUARANTEED FINEST RECEP-
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Hil, Model 303 — Channels 14-83. O the UHF ANTENNA with the highest signal gain that is specially de-
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| |
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piral Antennas!
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tions, societies, and chambers of com- merce.
The associations are listed in six basic sections covering: trade, busi- ness, agricultural, and governmental; scientific and engineering; educational and social welfare; medical and health; general associations; and chambers of commerce.
The book sells for $15.00 a copy and is available direct from the publisher.
TERMINAL BLOCKS
Curtis Development & Manufactur- mg Co., 3266 N. 33rd Street, Milwau- kee 16, Wis., has compiled data on its line of terminal blocks and terminal block kits which it is issuing as con- densed catalogue No. 556.
This 8-page brochure includes a tech- nical description, specifications, and current prices on the firm’s entire line. A new selector chart designed to pin- point the best block for each applica- tion is also included.
The catalogue suggests combinations of various types of terminals within the same block for most convenient terminating of high current, control, and power circuits in a minimum space and with reduced cost.
This publication may be had by writ- ing to John Eschweiler, sales engineer of the firm.
“MAGNEMITE" PORTABLE
Amplifier Corp. of America, 398 Broadway, New York 13, N. Y., has issued a 4-page data sheet giving com- plete information or its ‘“Magnemite” portable, a battery-vperated, spring- motor tape recorder.
The brochure describes in detail fea- tures of all fifteen models available in the line. A variety of single and multi-speed models is offered and the brochure tabulates all the pertinent data. Various mechanical and electri- cal components are fully described and individually illustrated.
Copies of this brochure will be sup- plied upon request to the manufac- turer.
METER CATALOGUE
Greibach Instruments Corporation has issued a new 8-page catalogue de- scribing its line of meters for factory, field, and laboratory use.
The publication includes two full pages of charts and diagrams describ- ing the variety of scales and ranges available while another section illus- trates some of the accurate meters.
Copies of this catalogue are avail- able by writing Lawrence C. Oakley, engineering sales manager, in care of the company at Metuchen, N. J.
DUAL-RANGE POWER SUPPLY
Electro Products Laboratories, 4500 Ravenswood Ave., Chicago 40, IIl., has issued an illustrated catalogue sheet which describes its two-range d.c. power supply for servicing transistor radios.
The unit described, the Model D612T, offeys power ranges of 8 and 16 volts
anditis designed to operate, test, and |
Hi-Fidelity AM-FM Radio
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mplete Hi-Fidelity FM-AM radio made by one the top manufacturers. This set is ideal for custom in- stallations. Built-in 14 Watt Hi-Fide r. rate
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RADIO and TELEVISION ELECTRONICS
in all Technical Phases New Classes (Day and Evening) Start 1st of ® Dec., Mar., arom _ Free Placement Service for For Free Catalog write Dept. “RNTS RCA INSTITUTES, INC. A Service of Radio Corporation “of America 350 WEST 4TH ST., NEW YORK 14, N. Y.
Save time — Step up efficiency in ELECTRONICS
DESIGN
Here’s a wealth of technical help for efficiently handling electronics de- sign problems—heip that
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You'll find electronics mathematics
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ELECTRONICS DESIGN LIBRARY Edited by Markus and Zeluff, Efectronics Magazine 4 vols., 2151 pp., 9 x 12, 3534 illustrations Contains 1083 articles culled from recent issues
to design of electronics Special price equipment. The 4 big vol- saves you $6.00 umes are: Electronics for Regular cata- Engineers, Handbook of In- logue price of dustrial Electronic Circuits, books totals Electronics Manual for Ra- $39.00; under dio Engineers, and Electron- this offer, price ics for Communication
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RADIO & TELEVISION NEWS
service all auto radios, including those using transistors from a.c. lines.
This data sheet is available by writ- ing R. C. Crossley in care of the com- pany.
CRYSTAL CATALOGUE
U. 8. Crystals, Inc., 1342 S. La Brea Ave., Los Angeles 19, Cal. has issued a 6-page catalogue listing hundreds of crystals which the company carries in stock.
Crystals for the amateur, experi- menter, and commercial user are all listed in tabular form. Special fre- quencies can be supplied on a custom basis, the company doing the regrind- ing.
Information on crystal sockets for use with the units described is also included in this free catalogue sheet.
“MURDER IN THE MODEL SHOP"
Servo Corporation of America, New Hyde Park, N. Y. has issued an amus- ing catalogue-cum-“detective story” entitled “Murder in the Model Shop.”
Written in “thriller” fashion, the | story recounts the solution of servo |
system and instrument design prob- lems by use of the company’s “Servo- board” electro-mechanical assembly kits.
Copies of this 48-page booklet will be supplied without charge as long as the present printing lasts. Write the manufacturer direct.
NEW MILLER CATALOGUE
J. W. Miller Company, 5917 South Main St., Los Angeles 3, Cal. has just released its new general catalogue, No. 57-A.
This 32-page publication lists nearly 1000 different replacement coils for television sets, radios, etc. Of particu- lar importance is the new series of transistor antenna rods, oscillator coils, and i.f. transformers. The listing also includes a complete line of adjustable r.f. coils and chokes.
The components are pictured, with complete electrical and mechanical specifications provided on each item. An elaborate and complete index fa- cilitates locating a specific component.
SHURE FACILITIES
Shure Brothers, Inc., 222 Hartrey Ave., Evanston, Ill. is now offering a descriptive brochure covering its new plant and manufacturing facilities.
The brochure outlines the scientific reasons why the firm will be able to serve its manufacturers and distribu- tors more efficiently than ever. The new plant will be used for the manu- facture and design of microphones, phonograph pickup cartridges, mag- netic tape recording heads, and other precision electronic components.
A copy of the brochure is available from the Sales Department of the company.
INDIVIDUAL SCHEMATICS
individual schematic diagrams cover- ing receivers dating back to 1926, Su-
January, 1957
Short description of a Small Efficient TV System...
1 antenna..IN 8 set lines .. OUT 10 db signal ..GAIN
all with
DISTRIBUTION AMPLIFIER
model DA8-B
approved for Color-TV
$9950 List
Ideal for garden apartments, motels, TV showrooms, de- luxe home installations and other small TV systems. The DA8-B is a broadband, all-channel unit that requires no tuning, impedance matching devices, preamps or other special fittings.
Features and Specifications:
low me all-triode circuit
More Gon 10db gain on all VHF Channels iain isolation in excess of 22db
fievielen for 75-ohm cable or 300-ohm twin lead sadn overload through 10:1 gain control range Builtin power supply
Designed for continuous duty operation
NOTE: For larger systems, Blonder-Tongve will furnish Free planning service on request. Sold by Radio-TV Parts Distributors and Jobbers. Write for Installation Details and FREE Booklet—“TV for 2. or 3. or More” Dept. KA-4
‘ BLONDER-TONGUE pope ond <a aren
In response to a steady demand for | LABORATORIES, INC. rea per er gyre Re
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‘SENCORE CHECKER
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AT LEADING DISTRIBUTORS EVERYWHERE
Transistor ester ¢ Leakage Checker * Filament
INSTRUMENTS CORP. 171 OFFICIAL RD., ADDISON, ILL.
FILAMENT;
preme Publications, 1760 Balsam Road, Highland Park, Ill. has established a service whereby radio data will be available for 40 cents each while TV service material is priced at 75 cents per section for any one model.
The publisher will ship all material airmail, which should be a boon to technicians who have old sets on their benches and find they have no service data covering the receivers.
Full details on this new service and a free 48-page list of available mate- rial will be supplied on request.
C-D CAPACITOR DATA
Cornell-Dubilier Electric Corpora- tion of South Plainfield, N. J., is cur- rently offering copies of engineering bulletin No. 179 which describes and illustrates its new line of rectangular case a.c. capacitors.
The Type KGN units, rated at 236, 330, 440, and 660 volts a.c. and avail- able in capacities from 1 to 60 #fd., are housed in compact, space-saving cases. Complete electrical and physical specifications are given on each of the units currently in the line.
The company will supply a copy of this bulletin on request.
BINDING POST BROCHURE
The Superior Electric Company, Bristol, Conn., is now distributing a colorful brochure describing its line of 5-way binding posts for a variety of electronic applicaticns.
Bulletin BP656 describes the binding posts as being available in five differ- ent colors, in nickel-plated and nylon plastic types, and with a new soldering tip. Mechanical and electrical specifi- cations are provided on these com- ponents along with a tabulation of the various units in the line.
SENSITIVE RELAYS
Hedin Tele-Technical Corporation, 87 Dorsa Ave., Livingston, N. J., is now offering new literature on its line of sensitive relays.
The sensitivity of these relays is described as starting as low as 5 mw. per contact up to several watts. They are available for either a.c. or d.c. applications in contact combinations from s.p.s.t. to t.p.d.t.
Those wishing full details on the line should contact the manufacturer for literature.
BOOK ON DE FOREST The Mercer Publishing Company, 16 E. 52nd Street, New York 22, N. Y. has issued a 12-page, 5”x7”" booklet en- titled “Lee de Forest, Father of the Radio Industry” in honor of the 50th anniversary of Dr. de Forest’s inven-
tion of the grid vacuum tube. Designed for mass distribution, the publisher suggests that the booklet might be of interest to company em- ployees, stockholders, dealers, custom- ers, schools, etc. The back cover of the booklet is left blank for a company im-
print, if desired.
The booklets are available at a cost of from 3 to 10 cents each, depending RADIO & TELEVISION NEWS
on the quantity ordered. Minimum or- der is $1.00 (10 copies). Write the company for quantity prices.
B-T TELEVISION EQUIPMENT
Blonder-Tongue Laboratories, Inc. of Westfield, N. J., ‘has issued a four- page data sheet covering its line of in- dustrial and home TV equipment and accessories.
Included is data on an industrial TV camera, a booster and antenna booster, u.h.f. converters, ‘““Masterline” TV sys- tem units, cable connectors, “Add-a- Unit” TV system gear, and “Exact- Match” accessories.
Copies of this data sheet will be sup- plied without charge on request.
Harrison Radio Corporation, 225 Greenwich Street, New York 7, N. Y. is handling the distribution of the “Daiger Global Time Conversion Sim- plifier” which is designed especially for the amateur DX-er and the short- wave listener.
Printed in two colors, the chart is designed to be affixed to the hamshack wall for fast and ready reference. The chart is available from the distributor for $1.00 a copy postpaid. Remittance should accompany all orders sent to the company.
BASE STATION ANTENNA
A colorful brochure describing a 450 mc. base station antenna has been released by Andrew Corporation, 363 East 75th St., Chicago 19, II.
Bulletin 8417 pictures and describes the antenna and provides a gain pat- tern chart on the Type’201. A table
showing improvement in relative gain
obtained in an existing system through |
use of the company’s antenna is also included.
Write the company for a copy of this brochure, complete system infor- mation, or for a copy of its general Catalogue 21.
“TWIST-MOUNT™ ELECTROLYTICS
Pyramid Electric Company, 1445 Hudson Blvd., North Bergen, N. J., has
issued a two-color, 18-page booklet |
listing all of its ‘““Twist-Mount” elec- trolytics.
Form TMR-1 contains pertinent in- formation about the line which is available in single, dual, triple, and quadruple units. The units are de- signed for 85 degree C operation and are assembled in aluminum containers as protection against moisture.
The booklets are being handled by
the company’s distributors and repre- sentatives or are available from the manufacturer direct. ELECTRON MICROSCOPES A 4-page folder which lists engineer- ing and application information for the
company’s EM-100B and EM-75 elec- |
tron microscopes is being offered free by the Instruments Division, North
American Philips Company, Inc., 750 | S. Fulton Ave., Mount Vernon, New |
York.
Forty-four typical uses for electron microscopes are tabulated along with operating data for two units—one de- signed to handle the most difficult problems and the other for majority cases where minimum investment is
important. —30-
Development of the world’s smallest known radar set, for use in battle area sur- veillance, was announced recently by the Department of the Army. Unit, built by Sperry Gyroscope Co., can spot a single enemy moving a half-mile away in darkness er fog; vehicles or large groups much farther away. Lightness and ruggedness is attained by eliminating a cathode-ray tube and substituting audible signals to indi- cate the presence of an object. Set is self-contained in a drum-shaped metal case, 14 inches high and 14 inches long. The low power needed by the set is supplied by a lightweight motor generator that is easily transportable on foot by one mem- ber of a two-man observation team. The weight of set and generator is 85 pounds.
|
January, 1957
BUILD THE BEST
knight- kits
knight-kits
knight-kits
knight-kits .
WHEN YOU BUILD A KNIGHT-KIT.
YOU BUILD THE BEST
For a Complete Selection of
SEE PAGES 105-111
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Conte: Photocell "Circuits (Continued from page 59)
cell is dark. The wiring of the output receptacle is governed by the type of operation required. V: may be either a 6C4 or a 12AT7 with the sections connected in parallel. Higher oper- ating speed is obtained with the 12AT7. The relay must be capable of fast operation to take full advantage of this circuit. In some applications, a counter may be used in place of the relay.
A simple circuit which will sound a chime when someone enters a door- way is shown in Fig. 1E. For the di- rect operation of the 1 milliampere relay, a light intensity of 40 to 50 footcandles is required. This can be
conveniently obtained by placing a 25- |
watt lamp on the same side of the doorway as the photocell and reflect- ing its light into the cell with a mag-
nifying mirror placed on the opposite | door jamb. A shaving mirror is suit- |
able for this purpose. A small magni-
fying lens should be mounted in front |
of the cell, focused to obtain maxi- mum relay current. When the light on the cell is interrupted by someone entering the doorway, the relay will drop out and the chime, plugged into SO,, will sound.
Many other circuits and applications |
will occur to the experimenter as he works with light-sensitive cells. graph of Fig. 2 and Table 1 provide a useful guide to the operating charac- | teristics of the Clairex CL-2. When | working out other circuits, care should be taken not to exceed the 50-milli- watt power rating of the cell as opera- tion tends to become unstable above this point.
The service technician might well be able to add to his income by build- ing and installing light-operated equip- ment in stores, doctors’ offices, ma- chine shops, etc. Building the basic unit described in this article, or one of the other circuits, is a good way to
cially profitable devices. In a more frivolous vein, they can be worked into some amusing parlor tricks.
The Clairex type CL-2 photocell is
Fig. 2. Average characteristics of the Clair- ex Type CL-2 crystal photocell. See article.
The |
| tative “refresher course” for ° A | the technician, serviceman, get started toward designing commer- |
| ra ed a
MICROAMPERES
eit PFT CANOE mane
RAD-TEL
KIT SALE (2 1)
You get another identical kit abso- lutely free when you enclose this ad with your order! Applies only to same kit—no substitutions. AD MUST ACCOMPANY ORDER.
CERAMICON KIT
Kit of 50 assorted ceramic discs, bi- plates, tubular condensers. All con- densers popular sizes, used in TV & FM sets.
Get ~ anal ast oo “hit FREE with this ad
SOLDER LUG KIT
Kit of 48 assorted bac 2 od o> 3 terminal strips. rage £ y
for the price of
Get another eae rit FREE with this ad!
KNOB KITS Bag of 100, $2.95
6 Ibs. total Assorted home, auto, TV knobs. All col- e ors—plastic, wood, bakelite. Get one bag of $2.95 knobs FREE with CE - Be) this ad! Peaking, video IF, RF coils. Kit of 20.
2 Ibs. total 7 another 99c kit FREE with this a
INSULATED RESISTORS
Kit of 100, % to fd — 2 Ibs. - another 99c ie. TREE with this
Write Dept. RN-1 for FREE CATALOG OF
Tel TUBES &
PARTS TUBE CO. Other Tui FM > 1
No C.0.D.’s on this Not Affil. sale. Allow for post- age. SUBJECT TO MailOrderco, * PRIOR SALE. 115 COM ST
IRVINGTON II, N. J.
AN INDISPENSABLE HANDBOOK| All the Latest Developments in
RADIO, TELEVISION,
ELECTRONICS, HI-FI
A much-needed basic illus- trated manual for readers of this magazine. Covers all the latest developments in electronics, radio, television, hi-fi. An invaluable guide for the beginner; an authori-
FOR BEGINNERS AS WELL AS PROFESSIONALS
CONTENTS INCLUDE: Recent Developments in Electronics, Electrical Measuring Instruments, Oscillatory Circuits, Electron Tubes, Power Supplies, Amplifiers and Amplification, Tape Recorders, Acous- tics, Microphones, Transmitting and Re- ceiving Antennas, A-M and F-M Receivers, High Fidelity Systems, Transistors, Television.
a7: Nee
jays. or = COMPLETE
AMERICAN TECHNICAL SOCIETY Dept. RC-1, 1, 848 E. 5! 58th St., Chicago 37, 8
j AMERICAN TECHNICAL s SOCIETY, Dept. RC-1 i 048. Seth St, Chicago 37,
“ham” and Hi-Fi enthusiast anxious to keep abreast the numerous changes and improvements going on in this fascinating field. Writ- ten so anyone can under- stand it. 288 photos, charts, diagrams.
Fill out and mail coupon. Pay nothing now. Pay nothing to postman on delivery.
Simply pay bill after 5
Bes Please send me “Radio-Television and Basic ang for § days FREE EXAMINA TION. ees I | keep the book after 5 days, you may bill me for |
+ $4.95, plus shipping costs.
RADIO & TELEVISION NEWS
100 wa. at 100 v. and 2 footcandles
.01 wa. at 100 v. and 2 foot- candles after one minute.
Output decreases 6 db per octave throughout audio range for modulated
. light
Inverse function of illumi- nation. .15 second at 1 footcandle
Voltage—300 volts peak, a.c. or d.c.; Power—50 mw.
Entire visible spectrum. Maximum sensitivity near green portion. Good sensitivity to hard x-rays and gamma rays. Usable response near the infra- red region
Y%4” diameter, ¥2” long.
15%” leads, spaced 3/32”
Sensitivity:
Dark current:
Frequency response:
Time constant:
Maximum ratings:
Light response:
Size: Terminals:
Table 1. Specifications on CL-2 photocell. available from the Allied Radio Cor- poration, 100 North Western Avenue, Chicago 80, Illinois; Sun Radio and Electronics Company, 650 Avenue of the Americas, N. Y. 11, N. Y., and from the Clairex Corporation, 50 West 26th Street, New York 10, New York. The net price is $3.50.
The author wishes to thank Mr. Al Deuth of the Clairex Corporation for his cooperation in providing data nec- essary to the preparation of this ar-
ticle. -30-
“EFFORTLESS” INVENTORY By J. P, MURTHA
LTHOUGH the “bookless bookkeep- ing” system to be described is not new, it has worked out nicely for us in handling the problem of tube inventory control in our shop.
When a service job requires a new tube, we put the old one in the carton and give it to the customer after remov- ing the tube type identity tab from the earton. These tabs are kept in the caddy until calls for the day have been com- pleted. At that time, they are sorted by type and entries of quantities used posted to a “tube stock used” sheet which shows days of the week. At the end of each week, this sheet is totaled. The data thus collected serves as a guide in de- termining the types and quantities of tubes to stock. By making a carbon copy of the form, it can be used as an order to the distributor. The accompanying purchase order can read “per list at- tached.”
The same method can be used to con- trol and check operations in a large shop. Initially, it would be necessary to inventory and prepare a “stock on hand” inventory sheet for each technician’s tube caddy. Thereafter, the “week end- ing” inventory sheet would be used as the starting inventory for the following week. Each day stock would be replaced in the caddy by the stock clerk upon re- ceipt of tabs.
At the end of each week a physical check of each caddy would be made. The starting inventory plus or minus addi- tions or deletions should agree with totals of the “stock use” sheet. Such checks will accurately control tube stock.
The same method is adaptable to “in shop” bench repairs.
January, 1957
RADIO « TELEVISION ¢ INDUSTRIAL ELECTRONICS
THIS professional TRAINING IS THE KIND THAT
Really Pays Of!
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FIX ANY RADIO OR TV SET EVER MADE...easier...better...faster
Backed by the how-to-do-it methods so clearly explained in this one big 822-page book, you'll be prepared for fast, accurate service on any radio or television receiver ever made.
Radio & Television TROUBLE- SHOOTING AND REPAIR by Ghirardi & Johnson is far and away the world’s most modern, easily understood guide. Step by step, it takes you through each service procedure .. . from locat- ing troubles with less testing to repairing them promptly by fully- approved professional methods . the kind that enable you to handle tough jobs as slick as you now do the easy ones,
Best of all, the cost is only $7.50 (or see money-saving combination offer in coupon).
experienced servicemen, it is an easy way to “brush up’”’ on specific jobs; to develop better methods and shortcuts and to find fast answers to tough jobs.
Here are just a few of the sub- jects covered: Components and Their Troubles; Basic Trouble- shooting Methods; “Static” and “Dynamic” Testing; Practical Troubleshooting Tips and Ideas; AC/DC, 3-way Portable and Bat- tery Set Troubleshooting Prob- lems; Servicing Communications Receivers; a Complete Guide to Television Service; AM, FM, and TV Realignment Made Easy; Re- sistor, Capacitor, Inductor and Transformer Problems; Servicing Tuning, Selector and Switching Mechanisms; Loudspeakers; Serv- icing Recorders and Record-play-
iy,
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PAIR for 10 days AT OUR RISK!
LEARN BASIC CIRCUITS FULLY... and
watch service “headaches
It’s amazing how much easier and faster you can repair radios, television sets and even industrial electronic equipment when you know all about cir- cujts and what makes each one “tick.”
You locate troubles in a jiffy because pea aeew what to look for and where ook.
You make repairs lots faster, better and more profitably!
Actually, there are only a compara- tively few — circuits in modern equipment. Rad & Television RE- CEIVER CIRCUITRY AND OPERA- TION by Ghirardi and Johnson gives you a complete understanding of these as well as their variations. It teaches you to recognize them... to under-
The books that EXPLAIN SERVICE so you can really
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More radio-TV technicians have - trained from Ghirardi books than any others of their kind! Almost 1300 pages and over 800 pictures g and diagrams in these two new g books explain things so clearly it's next to impossible for you to go wrong. Each book is strictly up- to-the-minute .» . . NOT a re-hash 4 of old, out-moded material.
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Throughout, this 669-page book with its 417 clear illustrations gives you the kind of above-average pro- fessional training that fits you for the better, big pay jobs in either servic- ing or general electronics.
Covers all circuits in modern TV and radio receivers, amplifiers, phono-pick- ups, record players, etc.
Price only $6.75 ...or see money- saving offer in coupon. Examine it 10 days at our risk!
RN-17, RINEHART & CO., INC.
FREE EXAMINATION...casy sis
Dept. 232 Madison Ave., New York 16, N. Y.
Send noets indicated for FREE EXAMINATION. m #
Redie. & TV TROUBLE TING AND RE- PAIN, (Price $7.50) (Price $6.75) Cl COMBINATION OFFER . . . Both books only $13.00 (Regularly Ph separately $14.25 . . . you save $1.2
I will either remit price indicated plus postage § or return books pustpaid and owe you nothing. Radio & TV CIRCUI- § TRY AND OPERATION i
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$8.00 for TROUBLESHOOTING & REPAIR: $7.25 for CIRCU ITRY & OPERATION; $14.00 for both books; 4 Cash with order, but money refunded if you return books in 10 days, Co oe ee ee ee ee ee ee ee ee ee es a
103
TELEVISION
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AT HEALDS YOU LEARN BY DOING IN MODERN ELECTRONICS LABORATORIES
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new TO BE THE HAPPIEST CREATIVE ENGINEER IN CALIFORNIA {\ Engineers (E.E., M.E., Mfg., Sales) can \V have the kinds of jobs that creative men dream about. Top salaries and Vl\-\} benefits. Suburban locations in Fuller- ton, Newport Beach, Richmond, or ~ Palo Alto.
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ie ° oe, a REE - SU y-1 Precision x mir EVEeR? ORDER “
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100
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F.0.B. PASSAIC, N. J,
On orders of less than
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Free Postage on all prepaid continental U.S.A. orders. so¢ handling charge on all
orders under $5.00. 25% deposit on all}
100 tubes — 41¢ each
via Railway Express
C.0.D. Subject to prior sale.
Transistor Life Tests
| Show no failures after 18,000 | working hours at full power.
EPLACEMENT of transistors in
portable radios and other electronic equipment may never be necessary if they are used within the limits set by the manufacturer, a G-H engineer sug- gested recently. In addition he said transistors are rugged enough to with- stand the jolt of being fired from a mortar and still operate at full ratings. Speaking to a transistor reliability symposium sponsored by a Department of Defense advisory group, C. H.
| Zierdt, Jr., engineering consultant in | G-E’s Semiconductor Products Dept.,
reported results of tests run by the company on transistors made by it for
| use in consumer products as well as
in military and industrial electronic equipment.
Life tests started in 1954 on tran- sistors picked at random from regular manufacturing lots show no failures after 18,000 working hours at full pow- er. This is equal to maximum load on the transistors eight hours a day for six years. Further, it was stated that it is now impossible to tell if the transistors ever will fail because they still look and act like new transistors. By comparison, specially constructed long-life vacuum tubes have a survival record of only 50 per-cent after less than half this time at full power. Vacuum tubes used in home radios have an even shorter life.
To check his results on the tran- sistor life test, Mr. Zierdt said he test- ed 2050 transistors picked at random from ten different manufacturing lots between January and May of last year. Results of this check showed that only one-quarter of one per-cent of the transistors could not be operated at peak ratings after 1000 hours at full power. All of the transistors were still usable in portable radios. The other 99% per-cent of the transistors tested showed no signs of wear what- ever.
Other test results included evidence that transistors are- capable of with- standing substantial doses of nuclear radiation. Also it was found that ger- manium transistors are capable of op- eration at 100 degrees C. (212° F.) and storage at 135 degrees C. (275° F.). Previously, the upper operating tem- perature limit of germanium transis- tors was thought to be 85 degrees C. (185° F.) and the upper storage limit at 100 degrees C, (212° F.). This means that germanium transistors may be used in more military and industrial applications where higher tempera- tures are encountered.
RADIO & TELEVISION NEWS
BUILD THE BEST— —=— Kknight-kits!
LOWEST COST LATEST DESIGN EASIEST TO ASSEMBLE
i
MONEY-BACK GUARANTEE: KNIGHT-KITS FULLY MEET PUBLISHED SPECIFICATIONS, OR WE REFUND YOUR MONEY.
knight-kit LOW-COST GENERAL-PURPOSE 5” OSCILLOSCOPE KIT Feature for Feature the World's Best Oscilloscope Value
Model F-146 This new oscilloscope delivers performance equal to wired units costing several $ 50 times more and defies comparison with any other ’scope kit at anywhere near its price. It’s the ideal choice for radio and TV servicing, audio work and hundreds of other applications—meets 90% of all ’scope requirements. Here are some of the features that make this kit a standout in its class: Phantastron Sweep Circuit—versions of this circuit are used in $1,000 ’scopes; provides high linearity of sweep from 15 to 150,000 cps. Regulated Calibration Voltage—fully regulated square wave calibrating voltage is injected into signal circuit by spring return switch. 25 Millivolts Per Inch Sensitivity—three times the sensitivity of other scope kits in its price class. Retrace Blanking —found only in high-priced ‘scopes. Vertical Amplifier—frequency response +3db from 3 cps to 1.5 mc (+6db to 2.5 mc). Input controls are frequency-compensated. Rise time, .25 micro- seconds. Impedance, 3.3 meg. and 45 mmfd. Includes positive and negative internal sync. Outstanding construction features: CRT protected by heavy rubber ring; sturdy stee! case with disappearing handle. For easy assembly: pre-cut color-coded wire; resistors carded and keyed to match instructions; printed circuit; laced wiring harness; “‘Step-and-Chek”’ con- struction manual with wall-size picture diagrams. Supplied with all tubes including CRT, all parts, graph screen, wire, solder. Size, 914 x 1334 x 1734". Shpg. wt., 26 lbs. Model F-146. Complete 5” Oscilloscope Kit. Net only FEATURING PHANTASTRON F-148. RF Demodulator Probe Kit. Net
LINEAR SWEEP CIRCUIT F-147. Low Capacity Probe Kit. Net
knight-kit TV-FM SWEEP GENERATOR KIT
Guaranteed Linearity - Fool-proof Calibration - Wide-Range - Electronic Blanking
All-new; precision-designed for lab use, TV and FM servicing, production line test- ing. Covers 300 kc to 250 mc continuous on 4 bands (all fundamentals). Center fre- quencies of VHF TV channels appear on scales. Exclusive KNIGHT-KIT sweep circuit assures perfect linearity —-RF sweep output in excess of 0.15 volts, flat within 1 db, is available on all bands. Sweep width continuously variable, 0-13 mc. Dual crystal marker oscillator and input for variable marker (RF Signal Generator on
’ ‘ next page is ideal). Phase control provides blanking shift, 0 to 180°. Step-type and continuous output controls; separate marker amplitude control. Filter connected to 0-50 mc output jack provides 20 db attenuation of frequencies above 50 mc to assure pure, fundamental output. Sweep voltage for ’scopes on front panel. Pro-
Model F-123 fessional-looking blue-finish steel case with gray panel. Has “disappearing”’ handle. 8144x12x7%". With all parts, tubes, test cable, solder and multi-color pre-cut wire.
7) Oe Less crystal, Shpg. wt., 13% lbs. $44.75
EASY PAYMENT TERMS Model F-123. TV-FM Sweep Generator Kit. Net only........... P-286. 4.5 mc Crystal (.005%). Net : ns - $4.80 P-143. 5.0 me Crystal (.02%). Net......... tet $3.95
P-145. 10.7 me Crystal (.02%). Net........... Tore . ne $3.95
: SEE FOLLOWING paces >
ALLIED RADIO
as a
Use any 20,000 ohms/volt VO
Ready to build. Shpg. wt., 5 Ibs.
et 4 os
knight-kit 5” ALL-PURPOSE WIDE-BAND OSCILLOSCOPE KIT 2 Printed Circuit Boards « 5 Me Width for Color TV
Model F-144 Wide-band, 5” Oscilloscope; equals or betters the performance of commercially- 00 wired 'scopes costing several times the price. Two printed circuit boards and $ laced wiring harness assure wiring accuracy and uce assembly time. Ideal for lab use, color TV servicing and high frequency applications. Provides unusually wide sweep range—/rom 15 to 600,000 cps. fe in at frequencies as high as 9 mc. Vertical response, 5 cycles to 5 mc. Response, down only 1 db at 3.58 mc color
burst frequency; down only 3 db at 5 mc. High vertical sensitivity of 25 mv/inch. Input capacity 20 mmf and 3.5 megs. Outstanding features: cathode-follower vertical and horizontal inputs;
2nd anode provides 1400 volts high-intensity trace; push-pull vertical and horizontal amplifiers; positive and negative locking; faithful square wave res ator; Z-axis input for intensity modulation; one volt P-
trol; blanking circuit to eliminate retrace lines; DC positioning control. 4 parts. Handsome, professional, blue-finished steel case with ‘disappearing’
all tubes an
handles. 14% x 94% x 16”. Shpg. wt., 40 lbs. Model F-144. Wide-Band 5” Oscilloscope Kit. Net only
F-148. Demodulator Probe. Net. . $3.45.
NEW knight-kit VOLTAGE CALIBRATOR KIT
Model ] y hoa
F-136
Permits the use of any scope recision peak-to-peak AC voltmeter. Provides a true square-wave voltage on sco screen. Range switch and cali- brated potentiometer permit selecting any voltage be- tween .01 and 100 volts, in 4 ranges. Fifth position of switch feeds external signal to scope for comparison. Constant output on line volt. variation from 80-135 v. +6% on all ranges. Shunt capacitance only 15 mmf.
calibration. Direct coupling of output provides ground reference for DC scopes. Portable cas, 734 x 544 x 4%".
Model F-136. Voltage Calibrator Kit. Net... $12.75
Model F-135
an ae
VISUAL-AURAL SIGNAL TRACER KIT
A remarkable value in an instrument which permits visual and aural signal tracing of RF, IF, video and audio circuits—has highest gain in its price class. Traces the signal from the an- tenna to the speaker. Reproduces signal at plate or grid connection of any stage. Identifies and isolates “dead” stages. Features: usable gain of 91,000; “magic eye’’ with cali- brated attenuators for signal pres- ence indication and stage-by-stage gain measurements; built-in 4” PM speaker; single probe with plug-in head gives instant choice of RF or audio tracing. Provides noise test; built-in watt meter calibrated from 25 to 1000 watts; provision for exter- nal scope or VT VM. Blue-finish steel case. Shpg. wt., 13 lbs.
Model F-135. Signal Tracer Kit. Net only
Model F-129 NEW
oe
6-12 VOLT BATTERY ELIMINATOR KIT
A valuable new unit for servicing auto radios, mobile gear, etc. Delivers continuously variable filtered DC output from 0 to 15 volts. Provides DC output at 0-8 volts or 0-15 volts. Continuous current, rating: 12.5 amps at 6 volts, 10 amps at 12 volts. Can also be used as battery charger. Oversize rectifiers and transformer for better regulation and long life. Two meters provide simultaneous current and voltage readings; ranges: 0-15 volts DC: 0-20 amps DC. Doubly protected: fused primary and automatic-reset overload relay for secondary. Heavy-duty binding sts. Blue-finish steel case with ‘disappearing” handle. With all parts, solder and pre-cut wire. 9 x 12% x 7%". Shpg. wt., 20 lbs. Model F-129. Power Supply Kit. Net only PY $37.95
nse; frequency-compensated attenu- calibrating voltage; astigmatism con-
omplete with CRT
> >
$69.00
F-147. Low Capacity Probe. 12 mmf. Net... . 3.45
knight-kit LOW COST
RF SIGNAL GENERATOR KIT
Model F-145 Build this wide-
9] Q75 sess ed Se
wired instrument. Ideal for align- ment of RF and IF stages in ‘jello and TV sets, and for trouble- shooting audio equipment. Delivers output on fundamentals from 160 ke all the way out to 110 mc; useful harmonics to 220 mc. Has built-in 400-cycle sine-wave audio oscillator for modulating RF; audio is also available externally. Features high-stability Colpitts ' circuit with precision-wound coils—no calibration necessary. Has or a VTVM for initial s — for external modulator. Maximum audio output, 10 volts.
| RF output, over 100,000 micro-volts. Step and continuous-type output attenuators. With all parts, tubes, wire and solder. Port- able case, 7 x 10 x 5”. Shpg. wt., 10 Ibs.
Model F-145. RF Signal Generator Kit. Net only
range extremely
two-thirds the cost
VE AMEE ES
$19.75
eee
knight-kit AUDIO GENERATOR KIT Model F-137 An ideal audio fre-
ences source for $ 50 check audio cir- 37 cuits and speaker re-
sponse. Covers: 20
cps to 1 mc in 5 ranges. ee voltage: 10 volts into 600
ohms impedance. Offers the +1 db to 1 meg.
-25% distortion from 100 c less than .5% when driving
enerator imp., 600 o!
at response of a lab standard— hms. Less than through the audible range; ohm load at maximum out-
put. Cont. var. step-attenuated output. 17 Ibs. Model F-137. Audio Generator Kit. Net only... .$37.50
knight-kit RESISTANCE SUBSTITUTION BOX KIT
Model F-139
$95
Simplifies determination of resistor values ed in a circuit. 36 stand- ard 1 watt resistance values be- tween 15 ohms and 10 megohms with an accuracy of 10%. 18-posi-
tion switch; also slide switch for multiplying values by 1000. Extra switch wafer serves as tie points, eliminating buss bar.5x3x2".Com- plete with test leads and clips. 2 Ibs.
Model F-139. Resis. Sub. Box Kit. Net .$5.95
knight-kit CAPACITANCE SUBSTITUTION BOX KIT
Model F-138
$595
switch selects all values quickly a:
Makes it easy to find capacitor values needed in a circuit. Provides 18 standard capacitor values from -0001 mfd. to .22 mfd., +20%. Values are 600 volts, except .15 and -22 which are 400 volt. 18-position easily.
In bakelite case, 5 x 3 x 2”. Complete with all a» parts, test leads and clips. 2 Ibs. Model F-138. Cap. Sub. Box Kit. Net. .$5.95
QUALITY ELECTRONIC TEST EQUIPMENT IN MONEY-SAVING KIT FORM
RADIO & TELEVISION NEWS
me wee
1000 OHMS/VOLT VOM KIT
Exceptional accuracy and versa- tility at ae low cost. Ideal for service shop, lab and Amateur use. Uses 414" meter (400 micro- amp movement) with separate scales for AC voltage and current, DC voltage and current, decibels and resistance. 38 ranges include: AC, DC and output volts, 0-1-5- 10-50-100-500-5000 (1000 ohms/ volt sensitivity); Resistance, 0- 1000-100,000 ohms and 0-1 meg.; Current, AC or DC, 0-1-10-100 ma and 0-1 amps; Decibels, —20 to +69 in 6 ranges. Uses 1% pre- cision resistors. 3-position func- tion switch and 12-position range switch. Complete kit with bake- lite case, (6%4 x 514 x 334"), bat- tery, pre-cut wire, solder and test leads. Shpg. wt., 214 lbs.
Model F-128. 1,000 ohms/ volt VOM Kit. Net only .$16.95
Model F-140 50 knight-kit $29 20,000 OHMS/VOLT VOM KIT
Outstanding quality and perform: ance at extremely low cost. Fea- tures 32 ranges; full vision 414” meter; accuracy +2% of full scale; 50 microampere sensitivity for 20,000 ohms /volt input resist- ance on DC; front panel “‘zero adjust’’ Single switch selects function and range. Range: AC, DC and output volts, 0-2.5, 10- 50-250-1000-5000; istance, 0- 2000-200,000 ohms and 0-20 meg.; DC ma, 0-.1-10-100; DC amps, 0-1-10; Decibels, —30 to +63 in 6 ranges. Uses precision 1% mul- tipliers. Moisture-resistant film- type resistors. Complete kit with bakelite case (6% x 544 x 3%"), batteries, pre-cut wire, solder a test leads. Shpg. wt., 5 lbs.
Model F-140. 20,000 ohms/volt
oh
knight-Kit RESISTOR- CAPACITOR TESTER KIT
Model F-124 Measures capacitance 50 and resistance by ac-
4 curate bridge method; checks for opens and
shorts in paper, mica
and ceramic capacitors; shows ower factor of electrolytics. rge dial shows capacitance and
resistance at a glance; balanced-bridge circuit with ‘magic eye”’ null indicator measures power factor from 0-50%. Tests capacitors with rated voltages applied. 5 test voltages: 50, 150, 250, 350, 450. Capac- ity ra : 10 mmf to 1000 mfd in 5 ranges. Resistance ranges: 100 to 50, ohms and 10,000 ohms to 5 megs. Accuracy, +10%. Auto- matic disc feature prevents after-test shock. Blue-finished steel case, 5 x 3 x 2”. With tubes and all parts. Shpg. wt., 8 lbs.
Medel F-124. Resistor-Capacitor Tester Kit. Net only... .. $19.50
NEW xnight-kite TRANSISTOR & DIODE CHECKER KIT
Model F-149 $ Checks leakage-to-gain ratio and noise level of all junction, point con- tact and barrier transistors. Also checks diodes, forward and reverse current con- duction of selenium rectifiers; useful for continuity and short checks. Easy-to-read meter. Features: spring-return leakage gain switch; calibration control; separate sockets for PNP and NPN transistors. Headphones or signal tracer may be used with checker for noise measurements. Case, 5x 3x 2”. With 22% volt battery. 2% lbs.
Mode! F-149. Transistor Checker Kit. Net $8.50
EASY PAYMENT TERMS: if your total KNIGHT-KIT order is over $45, take advantage of our liberal Time Payment Pian —only 10% down. Write for application blank.
ALL PRICES NET F.0.B. CHICAGO
(Po 9h ip ROR
knight-kit VIVM KIT with Printed Circuit Board Model F-125 An extremely stable,
95 and highly accurate $ VTVM. Greatly sim- 7% plified wiring—entire chassis is a printed circuit board. Maximum conven- ience in arrangement of scales; 3X AC and DC scale design permits | utilization of best portion of each § scale for most accurate readings. . Also measures peak-to-peak for FM and TV work. Ranges: AC P-P volts, 0-4-14-40-140-400-1400-4000; AC rms volts and DC volts, 0-1.5-5-15-50-150-500-1500; resistance, 0-1000- 10K-100K ohms and 0-1-10-100-1000 megohms; db scale, —10 to +5. AC response, 30 cycles to 3 mc. Low-leakage switches and 1% precision resistors. Balanced-bridge cir- cuit. 444” meter, 200 microamp movement. Polarity revers- ing switch. Input res., 11 megs. Shpg. wt., 6 Ibs. Model F-125 Printed Circuit VTVM Kit. Net only . .$24.95 F-126. Hi-Voltage Probe; extends DC to 50,000 Volts $4.75 F-127. Hi-Frequency Probe; extends AC to 250 mc. .$3.45
Wie
Model F-143 kmight-kit LOW-COST TUBE TESTER KIT 5 Offers high accuracy, top versatility and convenience $ at lowest cost. Tests 4, 5, 6 and 7-pin large, regular and miniature types, octals, loctals, 9-pin miniatures 2 and pilot lamps. Features test for new 600 ma series string tubes. Tests for open, short, leakage, ter continuity and — (by amount of cathode emission). 444” square meter with clear “GOOD-?-REPLACE” scale. With line-voltage indicator and line-adjust control. Choice of 14 filament voltages from .63 to 117 volts. Blank socket for future type tubes. Universal-type selector switches for any combination of pin connections. Single-unit, 10-lever function switch. Entire switch assembly is installed as a single unit— saves time and greatly simplifies construction. Illuminated roll chart
lists over 600 tube types. Shpg. wt., 14 Ibs.
Model F-143. Counter Model Tube Tester Kit. Net only... $29.7 5 Model F-142. Portable Model Tube Tester Kit. Net only... .$34.75
F-141. TV Picture Tube Adapter for above. Net only........ $3.75
eH ik ERR Rae. apalt Pe
knight-Kit LOW-COST : “IN-CIRCUIT” CAPACITOR CHECKER KIT
Tests capacitors while they are still wired in the circuit! Saves time and bother; an essen- % tial instrument for the service technician. Just press a button and the “magic eye” instantly shows opens and shorts (not leakage). Tests Opens and shorts on any capacitor of 20 mmf or greater capacity, even if it is in parallel with a resistance as low as 50 ohms. Tests for shorts may be made on any capacitor even when it is shunted by os low os 20 ohms. Blue-finish steel case, 7% x 5% x 5”. With tubes, all ports, wire and solder. Eosy to assemble. Shpg. wt., 5 Ibs.
Model F-119. Cop. Checker Kit... $12.50 Ae SBE RE ee eRe esc ine
Model F-119
12°
order fom ALLIED RADIO 100 N. western ave., CHICAGO 80, ILL 2
knight-kit “SPACE SPANNER” BAND SWITCHING
RECEIVER KIT
$] 5%
Model $-243
marine radio. Features hig
rectifier. Six controls: Bandspread; Bandswitch; Regeneration; 7x 10% x 6”. Shpg. wt. 41% lbs.
Model S-243. “‘Space Spanner’’ Receiver Kit. Net only $-247. Matching Cabinet for above. 2 lbs. Net
knight-kit errr J | beg
Thrilling Short Wave and Broadcast
Famous 2-band AC-DC receiver in easy-to-build kit form at a very low price. Pulls in thrilling short-wave (6 to 17 mc) and standard broadcast. It’s fun waeag + = | to amateur, aircraft, police and
ly sensitive regenerative circuit. Bandswitch selects broadcast or short wave. Has 4” PM speaker and beam-power output tube for plenty of volume; headphone connectors for weak signal listening; slide switch cuts out speaker. Uses 12AT7 regenerative detector and audio ee 50C5 power output, 35W4
’ ain ses a - ae ee 2-stage amplifier; each unit has 4” PM dynamic s
Model S-735 s] 7*
RADIO & TELEVISION NEWS
ane
NG, INSTRUCTIVE...
ie 0. Comet "we
——
Model S-295 $] 47s
NEW kmight-kie TWO-WAY INTERCOM KIT
New low-cost, easy to build intercom system kit. Ideal for use in home or office. Consists of Master unit Remote unit, each with press-to-talk switch. Remote unit may be left “open” for answering calls from a distance, for “‘baby- sitting’, etc. Remote may also be connected for “‘private”’ operation—cannot be “‘listened-in”’ on, but it can be called nd can originate calls. Master unit includes high-gai
f. Complete with Antique White cabinets (434 x 644 x 4%): all parts, tubes and 50 feet of cable (up to 200 feet of cable can be added). For AC or DC. Shpg. wt., 7 lbs.
Model S-295. Two-Way Intercom Kit. Net only. $147 5
acai as 319%
3-WAY PORTABLE RADIO KIT
“OCEAN HOPPER” RECEIVER KIT
Tops for exciting broadcast, long wave and short wave reception. Highly sensitive regenerative- type circuit. Excellent headphone reception; can be used with 3-4 ohm PM speaker on strong broadcast band stations. Supplied with plug-in coil for standard broadcast; covers Jong wave and popular short wave bands with coils below. Pulls in thrilling foreign broadcasts, police, ama- teurs and ai t. Controls: Main Tuning, Band- ae. Antenna Tuning. Off-On-Regeneration. ith all parts and tubes (less extra coils and headset). AC or DC. Shpg. wt., 5 Ibs. Model $-740. “Ocean Hopper”’ Kit $11.7. 5
EXTRA PLUG-IN COILS $-741. Long Wave, 155-470 kc. Net $-742. Short Wave, 1.65-470 kc. $-743. Short Wave, 2.9-7.3 mc. { Net $-745. Short Wave, 7-17.5 mc. {each $-744, Short Wave, 15.5-35 mc.
knight-kit LOW COST PHONO AMPLIFIER KIT
It’s easy to build this fine-performing, low-
“RANGER II” SUPERHET RADIO KIT
Thousands have built and enjoyed _the “Ranger” Broadcast Band Receiver. Care- fully 5 poe for easy construction and werful, sensitive performance. Latest perhet circuit; tunes 540 to 1680 kc; covers entire broadcast band and exciting police calls. Features automatic volume control, built-in preformed loop antenna, ball-bearing tuning condenser. Develops excellent tone uality from Alnico V PM dynamic speaker. pplied with following tubes: 12SA7GT con- verter; 12SK7GT IF amp.; 12SQ7GT det.- AVC-audio; 50L6GT audio output; 35Z5GT rect. Complete with handsome brown plastic cabinet (6 x 9 x 5) tubes, speaker, all parts, and instruction manual. AC or DC operation. Shpg. wt., 8 lbs.
Model S-735. “Ranger II’’ Superhet
Radio Kit. Net only $17.25
CRYSTAL SET KIT
hono
FAMOUS knight-kit
Thousands of beginners have started in radio and electronics by building the KNIGHT-KIT
A low-cost ble radio covering the fi nant heneies
sta t band from 535 ke to 1650 ke. Delivers excellent tion on AC or DC current or from - contained batteries. Sensitive Superhet circuit features automatic con- trol, scones c. apten, ae powe 5” i ic 8 er, efficient ferrite loop-stick antenna. Sup- plied with follo tubes: 1R5 con- verter; 1U4 IF amplifier; 1U5 detector- AVC-audio; 3V4 audio output. Complete with attractive portable case (754 x 10 x 5%"), tubes, speaker, all parts in- struction manual. Shpg. wt., 6 lbs. Model S-730. 3-Way Portable Radio Kit (less batteries). Net. $19.95
4-651. Battery Kit for above
Model S-261
s9ls
cost compact
amplifier. Ideal for use
in a portable phono-
Fe By =! add any
record player and a 3 to 4-ohm s er. Amp) works with crystal
or ceramic cartridges. Inverse feedback circuit for rich, clean tone
ne ve . Delivers full 144-watt output with less than .25 volt input.
ncludes efficient tone control; has AC outlet, controlled from ampli-
fier switch. Complete with tubes and all parts. Size only 44 x 7 x 4"°— fits into almost any portable phono case. Shpg. wt., 3 lbs.
Model $-790. Phono Amplifier Kit. Net only
crystal set. This feature-packed set delivers
loud, clear reception of local broadcast stations.
A nium crystal diode detector assures
high sensitivity and simple o tion—no crystal adjustment re- uired. ‘“Hi-Q”’ coil boosts sensitivity. Ball- ing variable capacitor ‘or easy tuning. With all parts and simple-to-follow instructions.
Shpg. wt., 1 lb.
Model $-261. Crystal Set Kit. Net only
$-267. Accessory Kit. 2000-ohm headphones and all parts
for outdoor antenna
Buy with confidence from ALLIED — America’s Pioneer in Electronic Kits
RADIO & TELEVISION NEWS
EASY-TO- BUILD HIGH PERFORMANCE | KITS © WIDELY USED BY MANY LEADING TRAINING SCHOOLS
NEW knight-kit ELECTRONIC PHOTOFLASH KIT
New fea*ure- Model S-244 pocked photoflash $ 50 Bit—desi ned for top qua We de- pendability— available at a money-saving low price. Ideal for black and white or color meres. te a Xenon-filled re- ector-bulb assembly gives over 10,000 flashes at less than ft each! 1/700-second flash freezes the fastest action. Has 50 watt-second out put. Provides light ny! pare wen J dayli pple! in spectral q permits the use of outdoor-type ndoors. Film gui number for color (ASA10) is 45. 2b. Designed for ““X”’ or “O”” shutters only. Requires sync cable (available from any ae supply dealer) and either battery or AC supply ted below. Com: —— outfit with battery weighs only 344 Ibs. Kit includes all parts, carrying case and easy-to-follow instructions. Shpg. wt., 3 lbs. Model $-244. Electronic Photoflash Kit. Net. $-246. AC Power Supply Kit. Easy to assemble. 4-626. Battery for eheve (Burgess U-200)
knight-kit TRANSISTOR RADIO kit Printed Wiring « Works from Penlight Cell
$763 $435 Variable Capscitr Tuning
Experiment with the marvel of transis- tors! Printed circuit requires no wir- ing—just assemble with a few solder connections and enjoy excellent recep- tion over the full AM broadcast band. No tubes to burn out—no crystal. Com- pact—fits in the palm of your hand— oneeee for months from a single penlight cell. Transistor provides plenty of power for strong headphone reception. Complete with ball moeersg transistor and penlight cell. Shpg. wt., 8 oz. Model $-765. Transistor Radio Kit $4.35 S-266. Accessory Kit. 4000-ohm head- phones and all parts for —— an- . - $3.15
FAMOUS knight-kit LAB KITS
6-IN-1 RADIO LAB KIT
Model S-770 Build Any
$795 of 6 Electronic
Projects
A fascinating and instructive kit. Enables you to build any one of the following projects: Standard Broadcast Receiver; Wireless “Home Broadcaster’’; Code Practice Oscillator; Code Practice Broadcaster; Signal Tracer; Sine Wave Generator. Perfect for be- ginners. Once basic wiring is completed, circuits may be changed without soldering. Safe to build and operate; only tools needed are screwdriver, pliers and soldering iron. ideal kit for students and beginners in electronics. Kit ineludes mounting board, tube, all parts and easy-to-follow instruction manual. Less headphone (also pom as mike). Shpg. wt., 6 Ibs. $-770. “‘6-in-1”’ Lab Kit. Net only ete. Single 10 1000-ohm headphone for above ¢-100. Ani kit for above
knight-kit WIRELESS BROADCASTER KIT
Model $-705 This fascinating unit makes it possible to “‘broad-
cast” witn phonograph or microphone through any
$ 50 standard radio receiver up to 50 feet away—with-
out any connection to the set. May be used with
hog or magnetic cartridge, or with microphone.
Broadcasts a clear, full-toned signal. igh- gain aa ee — using magnetic cartridge without need for exte
Complete with all ig be tubes, wire and solder Genk oak saheee-
Easy to assemble. Shpg. wt., 3 Ibs.
phone). 444 x 5 x 6”.
Build Any of 10 Electronic Projects
wonderfully instructive electron- ics kit. Ideal for experimenters, beginners—fun to build. Construct % a sensitive Broadcast Receiver; . Amplifier (for phono or mike); Wireless Phono Oscillator; Home **Broadcast Station’’; Code Practice Oscillator; Capacity-Operated a or Be bane one of four other fascinating projects. Low voltages;
and operate. Only tools needed are solderi Bored
screwdriver & and pliers. Perfect for self-instruction in circuit mentals, cked with practical applications. Kit Sechotes mounting bo , tubes, all parts, hardware, microphone, and 12- page builders’ manual. ‘Shpg. wt., 10 lbs. Model $-265. ‘‘10-in-1’’ Lab Kit. Net only... 4-112. Single 1000-ohm headphone for above ¢c-100. Antenna Kit for above
knight-kit CODE PRACTICE OSCILLATOR KIT Model $-239 Transistor Circuit — $395 sae by
Penlight Cell
Model S-705. Wireless Broadcaster Kit. Net only $-556. Microphone for above with 5-ft. cable
knight-kit PHONO OSCILLATOR KIT
Medel $-760 This low-cost se oscillator may be used with
any crystal pho are for “broadcasting” re-
$ 85 corded music through any standard radio receiver
up to 50 feet away. yn Fo no direct connection
to radio set. Operates on any frequency between
600 and 800 kc. Has controls for adjustment of modulation
level and selection of clear frequency on ra receiver. Uses
50L6GT tube and 35Z5GT rectifier. vir oy with all parts, tubes and instructions.4'4 x 444 x 44%". Shpg. wt., 1 Ib,
Model S-760. Phono Oscillator Kit. Net only ALL PRICES NET F.0.B. CHICAGO
An ideal code practice oscillator. Uses transis- tor circuit. Extremely low current consumption —powered by single penlight battery. Pro- vides crisp, clear tone (400 to 600 cps). Has input jack for earphone; screw-type terminal strip for key. In compact bakelite case (2% x 3% x 1%") with anodized aluminum panel. Complete with all ports, transistor, battery and easy-to-follow instructions. Shpg. wt., 1 Ib.
Model $-239. Code Practice Kit....$3.95
See Next Page for Amateur Kits
order fom ALLIED RADIO i00 N. western ave., CHICAGO 80, ILL. a
January, 1957
RADIO & TELEVISION NEWS
J
BUILD YOUR OWN QUALITY HI-FI AMPLIFIER!
knight-kit
BASIC 25-WATT LINEAR-DELUXE Hi-Fi AMPLIFIER KIT
Model S-755
445°
Williamson-Type Circuit Printed Circuit Board Chrome-Piated Chassis
This super-quality hi-fi basic amplifier is designed to satisfy the most critical listener. Intended for use with tuners incorporating built-in preamp or with separate preamp. Incorporates latest Williamson-type circuit and has potted matched transformers. Delivers maximum output of 45 watts. Frequency response is: +0.5 db. 10 cps to 120 kc, measured at 20 watts. Harmonic distortion is only .15% right up to 30 watts. Intermodulation distortion is only oy at 10
watts and only .4% at 20 watts, using 60 cps and 7 ke, 1:4 ratio. Hum level is —85 db
w full
rated output. Output impedance, 4, 8, 16 ohms. Input voltage for 25-watt output is 1.8 pot Uses two 12AU7’s, two 5881's, and a 5V4. Etched circuit is utilized in voltage amplifier and phase inverter stages to speed assembly. Has output tube balancing control, variable toma ing control, and on-off switch. Handsome chrome-plated chassis, 14 x 9 x 2”. Overall he
A deluxe true hi-fi om ape | equal in performance to amplifiers selling at over twice ~~ ase Complete with all parts and tubes. Easy to assemble. Shpg. wt., 27 lbs.
Model $-755. Basic 25 Watt Hi-Fi Amplifier Kit. Net only..............-..-+se00+5 $44.50
$-759. Metal enclosure for above; black finish. 3 Ibs. Net
“knight-kit 10-WATT HI-Fi AMPLIFIER KIT Model $-753 Chrome-Plated Chassis
Famous for — response
$ 50 and smooth uction
at low cost. ly 0.5 voit
— amplifier to full out-
put. Frequency response:
+ 1 db, 30-20,000 cps at 10 watts. Harmonic
distortion less than 0.5% at 10 watts. Inter-
mod. distortion less than 1.5% at full out-
t. Controls: on-off-volume, bass, treble.
nput for crystal pheno or tuner. Chromed
tic
cartridee ome. Matches 8 ohm speakers. pg. wt., 14
Medel $-753. Amplifier Kit. Net... $23.50
Model $-235. Preamp Kit for above ...$3.10
$-757. Metal Enclosure. 3 lbs..........$3.95
knight-kit 20-WATT HI-Fl AMPLIFIER KIT Medel $-750 Chrome-Piated Chassis
True hi-fi for less! Fre- 3 5/5 x oun response, +1 db, 20,000 cps at 20 watts. Distortion, 1% at 20 watts.
um and noise level: tuner
faget, 90 db we. 20 watts; phono 72 db low 20 watts. 4 inputs: magnetic phono.
microphone, crystal phono or recorder, tuner. Controls. Bass, Treble, Volume, Se-
ys — com tion among 3 for 78
ry & records. Built .* Preamp. Outputs: 4, 8, is sea 500 500 ohms. 23 Ibs.
Model $-750. 20-Watt Kit. Net .. $35.7 5
$-758. Metal Enclosure. 3 Ibs......... $4.15
$-752. Chrome-plated escutcheon for cabi-
net installation of amplifier. Net... . . $1
ALLIED RADIO
100 N. WESTERN AVE
CHICAGO 80, ILI
ALLIED RADIO CORP., Dept.01.A-7, 100 N. Western Ave., Chicago 80, Ill.
i Ship me the following KNIGHT-KITS: i Quontity Description Model No. Price : : : | $___.__ enclosed. For parcel post include postage (express is shipped collect). j Nome
Address j City. Zone. Stote.
Mee cewe comescesse
LOW-COST TOP QUALITY KITS FOR THE HAM
knight-kit Mode! S-255 50-WATT CW TRANSMITTER KIT
$ 9 5 Built-in Pi-Type Antenna Coupler Check the features packed into this new transmitter kit and you'll see why it’s one of the greatest Amateur values ever offered. Compact and versatile, it is the perfect low-power rig for the Novice or seasoned veteran. Features: 50 watts input to 807 final; high- efficiency 6AG7 modified-Pierce oscillator takes crystal or VFO without circuit changes; bandswitching cover- age of 80, 40, 20, 15, 11-10 meters; pi-section antenna output matches a impedances from 50 to 1200 ohms —permits use with any type antenna; no separate antenna tuner required. bag oy cathode k of ee goa, a. ay take-off lug 4. ment a -plus volta other equipment. ere o—_ and cabinet lenechor, Hisetinn . Copper. by , and coaxial SO-239 antenna vy teem be e ae lent = 7 . cks for VFO reads oI te or grid current o! crys’ fe. Supplied with all bes. Less crys and key. 8% x 1144x 8 he Neg x 7) Ibs.
Model $-255. 50-Watt Transmitter Kit. Net... $38.95
knight-kit SELF-POWERED VFO KIT Model S-725
Complete with built-in power su ! Careful design and vane regulation assure 8 ity. Excellent oscillator keying characteristics fast 4 *y with- out clicks or chirps. Full TVI su Has plenty
of bandspread: separate calibra scales for 80, 40, 20, 15, 11 and 10 meters; vernier drive mechanism. 2-
of transmitter. Output on 80 and 40 meters. With Spot- Off-Transmit switch for “no swish” tuning.
switch contacse for Fareting | ae other equip- ment. With all parts and tubes.
Model S-725. Self-Powered VFO. Kit. Net... $28.50
NEW xnight-xkit AMATEUR RF
“Z” BRIDGE KIT Model S-253 Measures stand- pai wave ratio $£85 R) and imped- ance of antenna Smpceess also for justing antenna networks for optimum results. Any v ah ma for null indicator. High accuracy with 20. ohm/v VOM. Correction Pers info — a for other V Ray ad 5 With coax input _ output Meters bo input and bridg . Calibrated brated dial gives seect 709 ion resistor for ~~ shaotieed SWR chart. 1% lbs. Model $-253. “Z”’ Bridge Kit. Net only . $5.85
RADIO & TELEVISION NEWS
Janu
January, 1957
LATEST ALLIED knight-kits
knight-kit FLYBACK CHECKER KIT
nit 94.950 |
Race through aot Genie circuit repairs for extra servicing its with this new Flyback and Yoke Tester! I mera checks all types of standard horizontal output transformers as well as linearity and width coils. Positively indicates shorted turns for any coil with a * greater than 1, and inductance between . and 2 henries. Determines continuity of any circuit with resistance from zero to .5 meg. Checks wider of inductances than any other simi- lar unit. Has highly legible 444” meter. Uses 6S4-A pulsed oscillator circuit. Supplied with all parts and test leads. 7% x 54 x 5”. Shpg. wt. 5\% lbs.
Rese Y-118, Flyback Checker Kit.
knight-kit 100 KC CRYSTAL CALIBRATOR KIT
Model - 0” New universal frequency
Y-256 calibrator to fit any com- mo me py on receiver—
iced so low every Ham
can afford it. Uses hermetically-sealed 100 KC crystal. Generates 100 Ke markers all the way up to 35 mc. Compact case is only 3 x 144 x 14";
has universal mounting flanges for mounting in Po
any of several positions. Requires only 6.3 v. at .15 amps and 150-350 v. at 3-6 ma. Includes
crystal zeroing trimmer and on-off switch which — mounts on case. Connects to receiver input. ~ Uses 6AK6 as electron-coupled oscillator.Com-
plete with formed and punched case, 100 KC oe 9 Nyman all parts and instructions. Shpg.
. knight-kit “IP TRANSISTORIZED — : ELECTRONIC LAB KIT
veo $545 i: Me at :
basi pe as ell You oo plete project
ic once. you com} pro.
after pro (10 in » os. just by inserting the
ot ice ‘ yt on the ditional sol-
ting leveloped! Includes all parts, colada <> bing none Shea iw Shpg. wt. 3 Ibe _T “ use order blank on opposite page
January, 1957
Model ¥-286. Crystal Calibrator Kit. $19), 50 .
‘Ham Communications
from
President’s Train
Record-breaking contacts with 45 states, 14 foreign lands.
O PROVIDE the President of the United States with extensive com- munications facilities from a railroad train, a communications car is included
in the President’s train. This car, the’
Albert J. Myer, has also been outfitted with amateur radio equipment which was extensively used during the recent 1956 presidential campaign to advance the amateur cause and to bring to the attention of appropriate parties a tre- mendous existing communications fa- cility, dedicated to public service.
The amateur station, W3WTE, op- erated by Al Hart, W4FB, recently completed a record-breaking series of contacts with stations in 45 states and 14 foreign countries. This was done in less than 21 hours of operation from a standing start 60 feet below street level at Union Station in Cleveland and along the trip to Washington, D. C.
The transmitting equipment used was an Eldico SSB 100A exciter and a SSB 1000 amplifier. These units were installed on their own rubber feet using wire braid as a snubber to prevent “walking” off the desk due to the car’s vibration. The receiver used was a military 390A which is manufactured by Collins. The antenna was the per- manent system which is normally used for official circuits. It consists of a capacity feed grid network atop the railroad car, which network excites a field whose lines of force go to ground through a return circuit, rising verti- cally on the car, thereby making the car itself a non-directional vertical radiator. A continuous recording was taken throughout the operation using an Ampex 400 recorder. —30-
Operating position in President's commu- nications car where contacts were made.
Your choice of school is highly important to your career in
INDUSTRIAL ELECTRONICS
RADIO- TELEVISION
ELECTRONICS COMMUNICATIONS
Become an
ELECTRICAL ENGINEER or an
ENGINEERING TECHNICIAN at
NMISOE in Milwaukee
Choose from courses in:
ELECTRICAL ENGINEERING Bachelor of Science degree in
36 months. Communications option (radio-tv) Power option.
ENGINEERING TECHNICIAN Assoc. in Applied Science degree — 18 months.
Electronics Communications Electrical Power.
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QUARTERS STARTING OcTO- BER, JANUARY, APRILZ JULY Choose wisely — your
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ARMEN
RADIO & TELEVISION NEWS
Handling FM-to-TV Interference
By GEORGE D. PHILPOTT
Slight alteration in oscillator coil of FM set will stop interference on specific TV channels.
ONFRONTED with. the problem of
FM receiver radiation interference on a television channel—or more than one channel—some technicians are at a loss as to the solution. In many cases, the offending FM set is upstairs, down in the basement, or may be on top of the kitchen range. Where a word of explanation to the customer is not sufficient to satisfy skeptical minds, the following alterations in the FM receiver might be necessary to eliminate the complaint.
The first step in the procedure is to determine exactly which TV channel suffers from interference; most likely, the customer will furnish this informa- tion quickly. Channels 5, 6, and 10 are the usual spots where FM receivers play havoc with picture reception. This is so because most FM sets with an if. frequency of 10.7 mc. radiate local- oscillator r.f.—at the fundamental fre- quency—on channels 5 and 6, and on the 2nd harmonic, on channel 10. This is the case where the FM set is de- signed so that the local oscillator tunes 10.7 me. below the incoming station frequency. Most currently produced FM receivers are designed to operate on the low side in this way because the local oscillator is more stable and gives greater r.f. output at a lower frequency.
When channels 5, 6, and 10 are the ones being interfered with, it is possible to eliminate completely the wavy lines and bouncing sound by changing the operating frequency of the offending FM set’s local oscillator. The task is not as rough as it might seem—if care is taken while making the alteration.
The oscillator coil in most FM re- ceivers usually consists of about four turns of copper or silvered wire. It is air wound and about % inch in diame- ter. Carefully remove a single turn from the coil, making sure that lead dress
and termination points are undisturbed. With one turn of the coil removed, the receiver's local oscillator will now be operating on the high side of the FM carrier. Slight re-touching of the oscillator trimmer will position the stations where they belong on the dial.
Some receivers require a nominal amount of coil adjustment to regain proper station tracking and alignment, but the average service technician should have little trouble in accom- plishing this accurately. With the re- ceiver’s oscillator operating on the high side, radiation from it will now fall in a portion of the radio spectrum not covered by the TV receiver. True, the FM oscillator will now radiate second-harmonic r.f. on TV channels 11, 12, and 13. However, second har- monic radiation is seldom _ strong enough at these frequencies to cause noticeable interference problems.
It is possible to reverse the above mentioned procedure when an _ inter- ference problem is prevalent on chan- nels higher in frequency than channel 10 because the FM oscillator is beat- ing above the carrier: add one turn to the oscillator coil and change its fre- quency to the low side. However, this condition seldom occurs.
A word of caution and a reminder: Should altering the oscillator coil as recommended here cause the receiver to fail in operation on all or a portion of the FM band, the oscillator tube should be checked by replacement and all circuit voltages should be tested. Currently designed FM oscillator tubes
and circuit components will function ©
properly at much higher frequencies than demanded in standard FM re- ception; oscillator failure after coil alteration could indicate other trouble in that portion of the receiver, and standard troubleshooting procedure should then follow.
MOUNTING AN OSCILLOSCOPE CALIBRATION GRID By ORRIN D. FACKLER
HE AUTHOR recently constructed a
Heathkit Model O-11 oscilloscope. An obvious difficulty with this scope is the inability of the thin plastic calibration grid to retain its rigidity for any length of time without becoming loose or warped.
One possible solution for this situa- tion. is to glue the grid to a wooden em- broidery hoop, as suggested by James F. Sutherland, (RADIo & TELEVISION News, November, 1956, page 184). An- other method, possibly better, can be used to correct the problem.
Sandwich the calibration grid between
two pieces of plastic. The plastic used by the writer was 1/16-inch transparent Plexiglas. However, the kind or thick- ness isn’t important. The plastic is cut into two circles, each having a diameter of 5% inches. The grid should also be trimmed to the same size and sand- wiched between the two pieces of plas- tic. These should be booked together by applying Duco cement to the edges and allowing sufficient time for the glue to dry. The finished unit may then be pressed into the felt-lined CRT front support with no danger of warping or twisting. —30-
RADIO & TELEVISION NEWS
Janua
January, 1957
$19.95 — Sonotone Cartridge
Brand New, top quality WEBCOR Chang- ; if S6 9 5 4Pole ers at a staggeringly low price! Many | “ high fidelity features including one t “a - ea) Moto four-pole motor and Sonotone * . : otor Sapphire Ceramic Cartridge. Oy at v :
, 3 Pune — age ~ wg v an ” records. Packed in specia ia R-OO14A Radio Shack Protective Carton. 16 ibs.
Mounting Base No. NR-9917.....$4.95 [Panny
ARCHER ‘LIPSTICK’ XTAL MIKE! Realistic Hi-Fi-System Y iise R 21.00 x yeh Amazing ie se WEBCOR 3-SPEED CHANGER can't Be Matched poet 4 te REALISTIC 10W AMPLIFIER _—For Less Than dk REALISTIC SPEAKER SYSTEM
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cost! Features Armstrong FM with Fos- ter-Seeley discriminator. 5 uv_ sensiti- vity. AFC, tuner RF stage, built-in AC = supply. Uses 6 tubes, 2 duals. ange 88-108 mc. Super- small —
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(Left) — 20,000 Q/v DC, 8,000 Q/v AC, 45 ua 3” meter, 5 KV DC scale.
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N NR-8296A
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N NR 7505
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$ a A. | T instrument Co. for $24.95 ith Encyclopedia Britannica, i Museum of Science and Industry
Complete weather forecasting kit has $11 mercury column. You build 3442” barometer, hygrometer, max.-min. ther- mometer, wind-cloud speed direction indicators. Free 48-page book. No. NR-9924. Ship. 10 Ibs. Railway Exp.
NR-9941
SR Te me ee ee
Tor RADIO SHACK Corp., 167 Washington St., Boston, Mass,
Brand New, Complete
1
ELECTRONICS | RUSH: 1. ; ;
CATALOG —57 |e $
{ 197 3. $ '
==e RADIO SHACK Corp 9iie ——' orp = Address !
BOSTON, MASS. — 167 Washington St. NEW HAVEN, CONN. — 230 Crown St Plans Order By Mail, No C.0.0.'s Please j
January, 1957 113
other method, possibly better, can be used to correct the problem. Sandwich the calibration grid between
X-CHECKER™
SERVICE-ENGINEERED! « helps solve a multitude of
TV-electronic problems
« from the Voice of Authority in sweep components
The new RAM X-CHECKER is a substitution box allowing easy substitution or insertion of a
itor or itor, or a series combination of both, in an electronic circuit. The resistance substitution range is from 0 to 2500 ohms, The capacitance substitution range is from 20 to 450 mmfd. Both ranges are continuously vari- able and the values may be read directly from the scale calibration. Accuracy of the calibra- tion is 10%. Dissipation of the resistor is 2 watts. Typical uses are:
* to eliminate sound bars on screen «+ to correct improper horizontal due to insufficient filtering action linearity, brightness or width of 4.5 me trap to determine value of burned
¢ to correct lack of picture detail due ilegible resistors or capacitors to insufficient h-f response of video to read unfamiliar codes amplifier stage to compensate for deterioration of parts ¢ to correct insufficient raster width «gndieniinties witean to ih © to correct improper magnitude of breadboard circuits
AGC or AFC pulse from flyback * to substitute directly for faulty circuit components $795 See it at your local distributor or write to Ram NEY for focal wholesale source.
CAPACITOR ANALYZER & RESISTANCE BRIDGE
~ Says! | Rowe Mfd by Clough Brengle to Navy Specs.—
Conventional analyzer for capacity—Range 10 MMFD-100MFD .. . Conventional ohm- meter 1 ohm to 10 megohms.. . operates
from 115V-60 cycles... op- $22.50
erating condition
Quality and Price
—_ and Repairs COMMUNICATIONS RECEIVER—Type RBL-5— CRT tube in set, Mfd by National for US Navy and Merchant Marine—Frequency 15-600KC in 6 bands. Per- fect for hams, distress band listeners, ships, ete.—Works from 115 volt-60 cycle. Gov't cost over $600—-Brand new with Tech man-
Ham) .ceccesesccccseccevesss ARC-5 TRANSMITTER ait 4MC Exc. Cond. W/Tubes $5.95
New W/Tubes 4.89
Fair Cond. W/Tubes 5.95
MC ARC- ‘ URECEIVERS
807W /5933—Ruggedized 807 feast $12.50 net) New—Sylvania $1.59 $15 doz. TUBE TYPE ince Rect.—New—boxed $1.29 $12.00 doz.
METER * 24" RD—Triplett—0- 200 Microamp DC—wht, scale—New $4.95
* Running Time—RW Cramer-—E21H— 110V—60 cycle—5 digit
* Weston 731—0-500 ~~ New 95
* Weston 731—0-8 A—!
DC New FOR: » connections, MINIATURE. MICROAMPMETER—0- 200u/a” De ments, usefu' DeJur 14/2" sq. New boxed cathode ission and 10 for 50.00 5.95 ea. tube. snenaaesen neg Ty ipamenttonal alte mom patna Open elements. Cor Gaasetion e be 2 righ avy pecs.—— aN ent j £ iv — operating condition—115V, 60 Cycle g20.00 ye — tubes and restores PROBE for above scope New ightness.
MAST SECTION MS-53—This is the section that can be screwed into each other to permit ex- tending to any desired length. 38.4” ea. section (1 meter)
jose out SPECIAL. Sold only in lots of 10. Former price 59¢ ea. Now—while they last—Bundle of 10
TEST SET—TS SEARS. Gen. & Power Meter 8700-9500MC $49.95 ST SET—TS 56/AP—360- -675MC—W acces.
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88 Cortiandt Street, New York 7, N. Y.
pressed into the felt-lined CRT front support with no danger of warping or
twisting.
RADIO & TELEVISION NEWS
Electrometer (Continued from page 67)
and an effort made to keep them clean and free from flux drippings.
The 100,000 ohm calibrating rheo- stat was soldered to the bottom of the copper chassis. The 5000-ohm wire- wound zero-set potentiometer was in- stalled on the panel opposite the ‘on- off’’ switch. The 117-volt leads to the filament transformer go to a terminal strip mounted on one of the screws holding the transformer. The one shown was cut out of a mounting board but any similar one could be used. The a.c. cord is fed through a grommet in the cover section of the cabinet. Wiring the device was some- what challenging because of the small space available but it can be done if care is used. The battery is wired in permanently since the tubes do not draw current when the filaments are cold. The plate current is about 600 ua. so the battery should have a rela- tively long life. A ground terminal is provided on the outside of the case near the porcelain insulator.
To calibrate the meter when the wiring is completed and checked, set the 100,000-ohm rheostat at its high resistance limit and turn the instru- ment on. Ground the terminal of the feedthrough insulator and zero the meter with the zero-set. Then apply a known voltage across the input termi- nals (a five-cell flashlight was used, E=7.75 volts) and adjust the rheo- stat until the meter reads the voltage applied. The 0-200 wa. scale corre- sponds to 0-20 volts across the input terminals. If the meter construction allows it, one can substitute a scale reading directly in volts. This com- pletes the construction of the instru- ment.
For normal use, a probe can be con- structed consisting of a 22-megohm re- sistor mounted in the end of a piece of plastic tubing. The wire connecting the resistor should then go to the ter- minal on the porcelain insulator. The value of the probe resistor is unim- portant as long as it is above 10-meg- ohms so that it provides proper isola- tion.
Fig. 3. Complete schematic diagram of simple vacuum tube electrometer.
+ 95> —
RADIO & TELEVISION NEWS
Ja
PHO’ data | minu' autor new |
Janua
BOSTON, MASS. — 167 Washington St. NEW HAVEN. CONN. — 230 Crown St
Order By Mail, No C.0.D.'s Please i
lel ee nn
January, 1957 113
for just
PHOTOFACT—the world’s finest TV-radio service data comes to you...keeps you right up-to-the- minute on new model releases...is delivered automatically by your Parts Distributor as each
new Folder Set is issued. Yes, for just 27¢ per day...
TOFAC Tear note veu courfe yer te
The regular monthly issues of Sam’s PHOTOFACT provide you with up-to-the-minute service data on new models as they are produced, for as
little as 27¢ per day! And this includes the “bonus” schematic service on new models hot off production lines to give you immediately the essential data you need.
With a current PHOTOFACT library at your fingertips, you can actually double your repair output, because you save valuable time on every job. YOU EARN MORE DAILY.
Learn how easy it is to sign up with your Parts Distributer to receive all Sams’ PHOTOFACT Sets regularly as published each month. Learn for yourself how a small investment of only 27¢ per day can mean GREATER income for you.
Exclusive PHOTOFACT features help you solve any service problem faster...help you earn more
PHOTOFACT offers you complete coverage on over 30,000 TV, Radio, Amplifier, Tuner and Changer models. And PHOTOFACT is a current service—keeps you right up with late model production— brings you these exclusive features...
Full Schematic Coverage: Famous “Standard Notation" uniform symbols are used in every schematic. Diagrams are large, easy to read and handle. Wave forms and voltages are shown right on the schematic for fast analysis. Transformer lead color-coding and winding resistances appear on the schematic. Schematics are keyed to parts lists and to parts on chassis photos.
Full Photographic Coverage: Photos of ali chassis views are provided for each model; all parts are numbered and keyed to the schematic and parts lists for quicker parts identification and location.
Alignment Instructions: Complete, detailed alignment data Is standard and uniformly presented in all Folders. Alignment fre- quencies are shown on radio photos adjacent to adjustment number —adjustments are keyed to schematic and photos.
Tube Placement Charts: Top and bottom views are shown. Top view is positioned as seen from back of cabinet. Blank pin or locat- ing key on each tube is shown. Charts include fuse location for quick service reference.
Tube Failure Check Charts: Shows common trouble symptoms and tubes generally responsible for such troubles. Series filament strings are schematically presented for quick reference.
Complete Parts Lists: Detailed parts list is given for each model. Proper replacement parts are listed (with installation notes where required). All parts are keyed to chassis photos and schematics for quick reference.
Field Service Notes: Each Folder includes time-saving tips for
servicing in the customer's home. Gives valuable hints for quick access to pertinent adjustments, safety glass removal, special
SPECIAL OFFER: If you return the coupon below and indicate your interest in receiving PHOTOFACT regularly each month, we will arrange to have delivered to you, ABSOLUTELY FREE, a valuable and attractive Wall Holder for the “Index to Photofact Folders" as well as the latest copy of the Index. Be sure to give your Distributor's name.
HOWARD W. SAMS &@ CO., INC. 2203 E. 46th St., Indianapolis 5, Indiana
(]! am interested in receiving all new PHOTOFACT Sets regularly as published each month. Send full details (Il understand there is no obligation on my part, and that I will receive without charge, the latest “Index to Photofact"’, along with Wall Holder).
(J! am a Service Technician: [_] full time; (_] part time.
My Distributor is:
advice covering the specific chassis, etc. omnes with PHOTOFACT by your side, you solve your Address: service problems in just minutes...you SERVICE City Zone. State
MORE SETS AND EARN MORE DAILY... January, 1957
115
Superior's New Model TY-11 HT J
SPECIFICATIONS
% Tests al! tubes, including 4, 5, 6, 7, Octal, Lock- to damage a tube by inserting it in the wrong in, Peanut, Bantam, earing Aid, Thyratron socket. Miniatures, Sub-miniatures, Novals, Sub-minars, + Free-moving built-in roll chart provides com- Proximity fuse types, etc. plete data for all tubes. Uses the new self-cleaning Lever Action Switches te Newly designed Line Voltage Control compen- for individual element testing. Because al/ ele- sates for variation of any Line Voltage between ments are numbered according to pin-number 105 Volts and 130 Volts. in the RMA base numbering system, the user NOISE TEST: Ph ie ane 1 can instantly identify which element is under * = TEST: Frhono-jack on front panel tor test. Tubes having tapped filaments and tubes plugging in either phones or external amplifier
will detect microphonic tubes or noise due to
with filaments terminating in more than one :
pin are truly tested with the Model TV-I! as faulty elements and loose internal connections.
any of the pins may be placed in the neutral The model TV-!I! operates on 105-130 Volt 60 Cycles
position when necessary. A.C. Comes housed in a beautiful hand-rubbed oak cabinet complete with
ere eo The Model TV-I! does not use any combination i type sockets. Instead individual sockets are portable cover. $ used for each type of tube. Thus if is impossible EXTRA SERVICE—The Model TV-i! may tor incorporated in this model will detect
be used as an extremely sensitive Condenser leakages even when the frequency is one per Leakage Checker. A relaxation type oscilla- minute. oe ee ee ee ee ee ee ee
Superior's New TRANS-CONDUCTANCE
TUBE TESTER
% NEWLY DESIGNED FIVE POSITION LEVER SWITCH TESTING TUBES ASSEMBLY. — — pb. —s — ages as required for plate and gri u
x Employs improved TRANS-CONDUCTANCE circuit. .
An in-phase signal is impressed on the input sec- a resulting in improved Trans-Conduct tion of a tube and the resultant plate current TESTING TRANSISTORS
change is measured. This provides the most suit- transistor can be safely and adequately tested
able method of simulating the manner in which only under dynamic cuuiiieenn. The Model 12
tubes actually operate in Radio & TV receivers, —_ wij] test all transistors in that approved a, ‘oad
amplifiers and other circuits. Amplification factor, quality is read directly on a special “transistor
plate resistance and cathode emission are all bm meter scale. correlated in one meter reading. The Model TV-12 will accommodate all transistors ie NEW LINE VOLTAGE ADJUSTING SYSTEM. 4 tapped ee og and Tetrodes, whether
transformer makes it p 0 cor e for od _— variations to a tolerance of better Giles sale tee o Model TV-12 housed in hand- * ye BUTTON—protects both the tube under some rugged portable cabi- s NET
and the instrument meter against - damage net sell r only
ALSO TESTS TRA NSISTORS! tue to overload or other form of improper switch-
‘yecc'wvie” PICTURE TUBE TESTER
NOT A GADGET—NOT A MAKE-SHIFT ADAPTER, BUT A-WIRED PICTURE TUBE ‘ TESTER WITH A METER FOR MEASURING DEGREE OF EMISSION—AT ONLY $15.85 cross
nomete:
Of course you can buy an adapter for about does not make nor do they recommend use of $5—which theoretically will convert your C.R.T. adapters or neon gadgets because a standard tube tester into a picture-tube Cathode Ray Tube is a very complex device, tester; or a neon type instrument which sells and to properly test it, you need an instru- for a little more and is supposed to be “as ment designed exclusively to test C.R. Tubes good as" a metered instrument. Superior and nothing else.
Tests ALL magnetically deflected tubes ... in the set... out of the set... in the carton! !
EASY TO USE: Simply insert line cord into any ture tubes from 7 inch to 30 inch 110 volt A.C. outlet, then attach tester socket to tube base (lon trap need not be on tube). Throw
t . _e switch up for quality test . . . read direct on Good-
© Tests for quality by the well estab- Bad scale. Throw switch down for all leakage tests. lished emission method. All readings
on “Good-Bad"™ scale. on thi: Model TV-40 C.R.T. Tube Tester for 11
@ Tests for inter-element shorts and leak- comes absolutely complete — buy. I ages up to 5 megohms. nothing else to buy. Housed in ; round cornered, molded bake- NET then + @ Tests for open elements. lite case. Only
@ Tests all magnetically deflected pic-
Try ar
and p cated
EXAMINE BEFORE YOU BUY! =
satisfie
USE APPROVAL FORM ON NEXT PAGE pave
RADIO & TELEVISION NEWS
Superior's New 20,000 OHMS PER VOLT
= ALLMETE
Includes services never before provided by an instrument of this type. Read and compare features and specifications below!
"A ee, line cord, a ay yer ar SPECIFICATIONS: pacity measurements, need be pluggec us 8 0.C. VOLTAGE RANGES: (At a sensitivity of 20,000 only when using that service. If is out ( y ) of “ne way, stored in its pliofilm com- oy oe. _ 0 to 15/75/150/300/750/1500/ 7500/ partment at all other times. 7 RC VOLTAGE RANGES: (At 2 sensitivity of 5,000 A built-in Isolation Transformer automati- Ohms per Volt) 9 to 15/75/150/300/750/1500/7500 cally isolates the Model TV-60 from the Volts. ow. line when the capacity service is 3 RESISTANCE RANGES: 0 to 2,000/200,000 Ohms, im use 0-20 Megohms. Selected, 1% zero temperature coefficient 2 CAPACITY RANGES: .00025 Mfd. to 30 Mfd. metallized resistors are used as multipliers 5 p.¢. CURRENT RANGES: . 0-75 Microamperes, 0 to assuring unchanging accurate readings on 7.5/75/750 Milliamperes, 0 to 15 Amperes. all ranges. 3 DECIBEL RANGES: — 6 db to + 58 db. Use of the latest type of printed circuit R. F. SIGNAL TRACER SERVICE: guarantees maintenance of top quali Enables following the R.F. signal from the antenna standard in the production runs of this to speaker of any radio or TV receiver and using that precise instrument. signal as a basis of measurement to first isolate the FEATURES Y A new improved type of high-veliage faulty stage and nally the component or circuit con- probe is used for the measurement of high — causing the tro Y A sensitive, accurate Volt-Ohm-Milliammeter voltages up to 30,000 Volts. This service will AUDIO SIGNAL TRACER SERVICE: with giant meter and mirrored scale. be required when servicing color TV receivers. Functions in the same manner as the R.F. Signal
ug- Tracing service specified above except that it is used An accurate direct-reading Capacity meter simply pe vin = in peehe ane one oo for the location of cause of trouble in all audio and
A Kilovoltmeter. amplifier systems. TRACER permitting the measurement of om cacek $¥.c00 eames sommelels
An R.F. Signal Tracer. ji id of trouble in the R.F. and 1.F gain and cause ‘ouble in ze .F, , , compres
An Audio Signal Tracer. circuits of A.M., F.M., and TV receivers. pg tne chy Ror goons . high:
Giant recessed 62 inch 40 Microampere Plug in the Audio probe and convert the waltages prehe; detnebabie line
meter with mirrored scale assures accuracy Mode! TV-60 into an efficient AUDIO SIGNAL cord: R. F. gnal Tracer Probe and Audio Signal
and easy-reading. All calibrations are printed TRACER. Measure the signal levels and com- in lerge. easy-to-read type. Fractional divi- parative efficiency of hearing-aids, public- ait, aheve aveseeorien ye sions are easily read with the aid of the address systems, the amplifier ti of Price complete. mirrored scale. Radio & receivers, etc. Nothing else to buy. Only S68 66 ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee
Superior's New Model TV-50
A versatile all-inclusive GENERATOR which provides ALL the outputs fer servicing:
A.M. Radio © F.M. Radio © Amplifiers © Black and White TV © Color TV 7 Signal Generators in One!
yY R.F. Signal Generator for A.M. yY Bar Generator
Y R.F. Signal Generator for F.M. Y¥ Cross Hatch Generator
VY Audio Frequency Generator Y¥ Color Dot Pattern Generator Y¥ Marker Generator
R. F. SIGNAL GENERATOR: VARIABLE AUDIO FREQUEN- BAR GENERATOR: The Model The Model TV-50 Genometer - fe —-
ciaed somialain bec nee mi Bg CY GENERATOR: In addition to TV-50 projects an actual Bar Pat- and F.M. alignment. Generates a fixed 400 cycle sine-wave audio tern on any TV Receiver Screen. Radio Frequencies from 100 Kilo- > ti - > "
cycles to 60 Megacycles on funda- the Model TV-50 Genometer pro- Pattern will consist of 4 to 16 mentals and from 60 Megacycles vides a variable 306 cycle to 20,000 horizontal bars or 7 to 20 verti- to 180 Megacycles on powerful harmonics,
ceeee HATCH GENERA- DOT PATTERN GENERATOR (FOR MARKER GENERATOR: The Model THE MODEL TV-50 OR: The Model TV-50 Ge- COLOR TV) Aithough you will be able to TV-50 includes all the most frequent- lutel % . comes absolutely com
pon. will project a cross- use most of your regular standard equip- ly needed marker points. The follow- a : c plete with shielded
cycle peaked wave audio signal. cal bars.
hatch pattern on any TV pic- ment for servicing Color TV, the one addi- ing markers are “7-7 189 Ke.,
ture tube. The pattern will tion which is a ‘‘must” is a Dot Pattern 262.5 Ke., 456 600 Ke., 1000 leads and operating consist of non-shifting hori- Generator. The Dot Pattern projected on Kc. . 2000 Ke., zontal and vertical lines in- any color TV Receiver tube by the Model 2 kc., 3 , 4.5 Me, 5 Me., terlaced to provide a stable TV-50 will enable you to adjust for proper Me. (3579 Ke. is the color burst cross-hatch effect, color convergence. frequency. )
SHIPPED ON APPROVAL NO MONEY WITH ORDER — NO C 0.D.
| SR cRe Te eine app ees aOR be ae 9 Ga nlentiomstinentinns ts treeemtmmtagor retrain hmabengins dee
instructions.
Try any of the instruments on this or the facing page MOSS ELECTRONIC DISTRIBUTING CO., INC. for 10 days before you Dept. D-316, 3849 Tenth Ave., New York 34, N. Y.
buy. if completely satisfied Please send me the units checked. | agree to pay down payment th within 10 days and: to pay the monthly balance as shown. It is . en send down payment understood there wilt be no Snanee or interest charges added. a Zone pret sas urther understood that should | fail to make payment when due, and pay balance as indi- the full unpaid balance shall become immediately due and payable. All prices net, F.0.B., N. Y. C.
cated on coupon. No In- CO Model Tv-tt Total Price $47.50 (© Model 60 Total Price $52.50 C] Model TV-12.......Total Price $72.50 ti ee $11.50 within 10 days. Balance $6.00 $12.50 within 10 days. Balance $8.00 $22.50 within 10 days. Balance $10.00 terest or Finance Charges monthly for 6 months, monthly for 5 months. monthly for 5 months.
Added! If not completely CO Model TV-50 Total Price $47.50 © Model TV-40. Total Price $15.85
T pose : $11.50 within 10 days. Balance $6.00 $3.85 within io days. Balance $4.00 satisfied return unit to us, monthly for 6 months, monthly for 3 months.
no explanati ee a cea ein eeeeatniss cannes iss cde bik sais pte eens a AR ciel des cscs al seh ii: Wiis hs cw im nin Winns cain ian ei ei
117
January, 1957
CRYSTAL
Manufacturing Headquarters
We will grind and etch crystals to your spec- ified frequency at the lowest cost in the in- dustry— supplied in popular FT-243 holders, 1%" pin spacing, .093” pin diameter—also in DC-34 holders, %” pin spacing, pin diameter .156 or FT-171 holders, pin spacing %4” with banana plug pins (fits 5-prong tube socket).
In FT-243 holders from 2000KC to 10,000KC. In DC-34 or FT-171 holders from 1100KC to 8000KC (specify holder warited).
Tolerance:
With thousands of frequencies in stock for immediate delivery, we list a few of the more popular frequencies. Write for com- plete listing. Cry.sals listed are in FT-243 holders but can be supplied in FT-171 hold- ers at 79 cents. (Add 5¢ per crystal for postage and handling.)
YOuR CHOICE
Novice Crystals 80 meter band within IKC of specified frequency from 3701KC to 3749KC in 40 meter band from 7152KC to 7198KC within IKC of specified frequencies 79¢; in DC-34, FT- 171 or FT-243 holders (specify holder wanted) 79¢. (Add 5¢ per crystal for postage and handling.)
Stock crystals in FT-243 holders from 5675KC to 8650KC in 25KC steps 50¢.
FT-241 lattice crystals in all frequencies from 370KC to 540KC 50¢. 500KC crystals...$1.00 455KC crystals. ..$1.00
Address all mail to Dept. R
JOBBERS & MANUFACTURERS W rite For Quantity Prices & Catalog
Texas Crystals
S
The Biggest Buy in the U 3 W. GRAND AVENU RIVER ALL PHONES — GLADSTONE
From Sun to Sound (Continued from page 43)
supplied by many ohmmeters on low resistance ranges is great enough to damage a transistor. Generally vac- uum-tube ohmmeters with battery supplies of 3 volts or less are safe—if used only on the Rx1000 range or higher.
When making ohmmeter checks of the circuit, always remove the trans- istors. Check the polarity of the ohm- meter test leads. The voltage supplied by an ohmmeter may harm electro- lytic capacitors in the circuit if ap- plied in reverse polarity.
Always watch your test probes! If a slip of a test probe shorts the tran- sistor base to the collector, the unit may be damaged. Most transistor ra- dios use a number of electrolytic ca- pacitors with low voltage ratings. Many capacitor checkers apply a test voltage sufficient to damage such a
| capacitor. Even a small voltage of in- | correct polarity can cause damage.
This must be remembered in making any ohmmeter checks of the transis- torized circuit.
Before connecting any signal gen- erator to the radio circuits, adjust the output attenuator for minimum out- put. Signal generators designed for vacuum-tube circuits can furnish more signal than a transistor can handle safely. Most transistor amplifiers have a relatively low input impedance. If the signal-generator output imped- ance is high, very little signal will be transferred to the transistor amplifier input.
Transistor Testing
The best way to check a transistor is by substitution. Transistors can, in an emergency, be checked for opens or shorts with an ohmmeter, providing a reasonable amount of care is taken.
An ohmmeter check is not a particu- larly good check. Never use an ohm- meter with a battery greater than 3 volts. Never use. the low resistance ranges; instead use the Rx 1000 range or higher.
In general, the forward current through a transistor should never be allowed to exceed 15 ma. A milliam- meter can be used to determine wheth- er any particular ohmmeter is safe to use in testing transistors. A junction transistor is more apt to become shorted than open. Transistors often become shorted because of excessive current flow, so a shorted transistor may be indicatjve of a circuit fault. For this reason, if a transistor is found to be shorted, check the circuit care- fully before installing a new one. A shorted transistor wili most often re- sult in increased power supply current drain. Thus, a quick and useful check is to measure the current drain with a milliammeter connected in series with the ieads from the battery power supply.
Care of the “Sun Power Pak"
The “Sun Power Pak” requires no service. However, a few precautions are worth noting. Occasionally clean the surface of the clear plastic with a cloth dampened in’ water. Do not use abrasive or window type cleaners. Use care to prevent scratching the surface of the clear plastic. When operating the set from an artificial light source, remember that the transparent plastic face will be damaged if exposed to ex- cessive heat. For this reason, never allow the surface of this plastic to be- come any warmer than to be just un- comfortable to the touch.
Care should be taken to prevent dropping the “Sun Power Pak.” Al- though it is sturdily constructed, it is possible to crack a silicon element if the “Pak” is subjected to a severe shock. If an element cracks, the unit will be inoperative. —30—
Over a hundred dental students and dentists at the Montreal General Hospital are
actually viewing this demonstration of dental techniques by of a
1 A
circuit TV setup. The camera is equipped with an Auto-Zoom lens to permit over- all as well as close-up views. An RCA ITV-6 television chain is employed here.
a
RADIO & TELEVISION NEWS
SHOW ANY PICTURE or PATTERN
at any time—ON ANY TV SET
: i
For Both Black & White and Color TV For Merchandising & Industrial Uses
Provides standard Indian Head Test Pat- Provides closed circuit TV system. Trans- tern for proper TV set alignment, and mits pictures or messages for advertis. stable White Dot and White Line Patterns ing, educational and commercial visual for color convergence adjustments. communication.
= [IBY] UN'AR-SCAN
PICTURE AND PATTERN
VIDEO GENERATOR
Make the most of this Complete Flying Spot Scanner It produces a composite video and sync signal that operates any standard black & white or color TV receiver. Can be used with one or more TV sets or fed into a master antenna TEST PATTERN TRANSPARENCIES system or community antenna system. Maximum AND ONE CLEAR ACETATE SUPPLIED resolution capability is well in excess of 450 lines; band width in excess of 5 mc. Projects and reproduces 1 Indian Head Test Pattern pattern or picture with high definition from any slide 2 White Dot Pattern transparency. Transmits messages typed or written 3 White Line Crosshatch Pattern on clear acetate. Makes convenient stand-by and break-in for community distribution operation. Rugged, $ 95 becncacdygdbevor mpg Ty se sng ~ gy on te compact, portable, and ready to operate. NET 199 Mt poker eed nee aah maaaat ee ae See your B&K Distributor, or Write for Bulletin No. 1000-N be used for special messages. Extra trans- eater anemgptaaies </> 9 BaKH MANUFACTURING CO.
3726 N. SOUTHPORT AVENUE - CHICAGO 13, ILL.
akc Be
om wn a we
Mode! 950 Dyna-Scan Pickup and RF Generator only. Model 400 CRT Model 750 CALIBRATOR
Enables you to make your own picture and pattern Dynamic mutual conductance Cathode Rejuvenator Tester. Designed to check and adjust
video generator, ot a saving Supplied with three tube tester. Accurately tests Tests and repairs TV picture —test instruments with labora-
test pattern transparencies and one clear acetate. 5 Net, $10995 — tubes. Net, $5495 tory accuracy. Net, $54.95 Net, $69.95
January, 1957 119
\ LAMPK 4
Enter the lucrative mobile-radio maintenance field —AT LOW COST!
Price $220.00 Type 105-B Frequency Meter
For free booklet “HOW TO
MAKE MONEY IN MOBILE-
RADIO MAINTENANCE,” and
other data—
USE COUPON TODAY ©
oe ae ae me ome Ge GD nD GD aD oD a ee LAMPKIN LABORATORIES, INC. MFM Division, Bradenton, Florida
At no obligation, please send me free booklet, technical data on Lampkin meters, and time- payment plan details.
Name
Address.
City.
" EREQUENCY
yy METERS
NOW... on
TIME PAYMENT PLAN
Lampkin’s new easy-payment plan makes it possible for you to start in mobile- radio maintenance NOW—and the monthly payments for your essential test equipment will be far less than your expected earnings.
You’ve read how mobile-radio is bursting its seams! NOW — you can start cashing in on this boom .-. with a low down payment!
Price $240.00 Type 205-A Modulation Meter
LAMPKIN LABORATORIES, INC.
MFM Divis
BRADENTON
S HOW TO WER RADIO -QUESTIONS
[RADIOL SSERVICE LIBRARY
per HERE IS LATE INFORMATION IN A HANDY FORM FOR TELEVISION AND RADIO REPAIRMEN, SERVICEMEN AND STUDENTS
AUDELS T.V. RADIO SERVICE LIBRARY- Highly Endorsed — Over 1500 Pages—1048 Illustrations &
Diagrams. 1001 Important | ©
Facts & Figures on Modern
Television, Radio, Electronic i
Devices at your finger ends. INCLUDES TRANSISTORS & Transistor Circuits, Record Changers, Rectifiers, P.A. Systems, Tape Recorders, Pho- nograph Pick-ups, F.M., Auto Radio; Radio Compass, Short
Wave, Radar, etc. ASK TO SEE IT!
iT WILL PAY TO KNOW— The Basic Principles—Con- struction—Installation—Oper- ation—Repairs—TroubleShoot- ing. Shows How to get Sharp, Clear T.V. Pictures. Install Aerials—How to Test. Ex- plains Color Systems, Methods of Conversion, Terms, etc. In- cludes Ultra High Frequency —Valuable for Quick Ready Reference and Home Study.
COMPLETE : t 2 VOLUMES °t thie information 7 DAY TEST—PAY ONLY $1 A Month
passe MAIL ORDER
fa Auoeis Publishers, 4 49 w. v.23: St. N tree trial, ro. a \ cotit remene 1 in
N.Y. y.10, 8 N.Y. i $6 is paid. Otherwise tI Lend
( for everything a hi-fi
_. GET THE MONEY-SAVING 1957
ALLIED CATALOG
~ Here’ ~ our co complete money-saving guide
' to Hi-Fi. Shows you how to select a cus-
tom Hi-Fi music system for your home at
no more than the cost of an ordinary
- phonograph. Tells you what to look for
~~ and how to save money. Offers the world’s
_ largest selection of complete Hi-Fi sys-
" tems as well as individual amplifiers,
tuners, changers, speakers, enclosures and accessories. Want to build-your-own?—
see the famous Hi- Fi KNIGHT-KITS. For
everything i in Hi-Fi—for everything in Elec-
=A b, ‘ronics, = we FREE 1957 ALLIED ‘cataiog.
ALLIED RADIO CORP. Dept. B-17 100 N. Western Ave., Chicago 80, Ill. “ (© Send FREE 1957 ALLIED Catalog
Address
i Zone. State. ‘
Ce a oe eo Sa
City.
BWA Oa Be me
Atomichron (Continued from page 63)
pole has the effect of conducting the atom into a sensing chamber and to a target.
The atom strikes the target, is ion- ized, and is attracted to the cathode of an electron multiplier, which ampli- fies the cesium input current a million times. The electron multiplier output current varies with the number and rapidity of impingements of ionized cesium atoms on the cathode. As the frequency of the r.f. field varies, the impingements on the cathode decrease, causing a change in the magnitude of the electron multiplier output current. This effect is used as the first step in adjusting the frequency of the r-f. signal to return it automatically to the standard value.
The frequency of the rf. signal which is applied to the atomic beam tube is derived from a 5 me. crystal oscillator. The output is multiplied to 9180 mec. Meanwhile, a synthesizer combines harmonics and subharmonics of the output of the basic 5 mc. oscil- lator in such a manner that when the synthesizer output is combined with the multiplier output in the adder, an output frequency is produced that is the nominal resonance frequency of cesium—9192.631830 mec. The cesium resonance frequency signal is also phase modulated by the 100 cps output of the modulation oscillator. The pur- pose of this modulation is to provide a determination of the direction of variation whenever the output of the crystal oscillator drifts.
The atomic beam output signal is amplified for transmission to one winding of a two-phase motor. The current applied to this winding by the feedback amplification system is auto- matically and continuously compared by the motor to the current supplied directly to the other winding of the motor by the 100 cps modulation oscillator. If the r.f. frequency is above cesium resonance, the motor will oper- ate in a direction which reduces the original error. If it is below resonance, the motor turns in the opposite direc- tion. This rotation is then transmitted through a gear box to a variable ca- pacitor which adjusts the output of the 5 me. crystal oscillator to bring the frequency at the atomic beam back to standard.
Since the crystal oscillator is under continuous surveillance for precision, the basic output is a 5 me. signal stablé and reproducible to 1 part in 10". Higher frequencies are taken from the multiplier and sub-multiples are taken from the synthesizer as shown in the diagram.
Because of its relatively small size and mobility, the Atomichron now makes high precision time interval and frequency control practical for naviga- tion, communications, and engineering systems without reliance on radio time signals.
RADIO & TELEVISION NEWS
for your gia short- -wave project. ‘iy , ; ip i / is EF
//
RCA-2N247
DRIET
TRANSISTOR
.. . enables practical construction of transistor RF- and IF- amplifiers operating at frequencies up to 20 megacycles
RCA-2N247 is a germanium p-n-p transistor featuring one of the most advanced < developments in transistor design which opens new possibilities for experimenters who waaieram rence build high-frequency circuits. The new transistor offers many practical advantages Service Type including: (1) excellent operating stability, (2) high-input-circuit efficiency, (3) good automatic-gain-control capabilities over wide-input-signal variations, (4) good presen pnt 2N105, signal-to-noise ratio—at frequencies well into the short-wave regions. 2N206, 2N215 Unique in design, the 2N247 uses RCA’s alloy-junction technique and includes a Class A Low-noise 2N175, 2N220 “built-in” accelerating field not available in conventional transistor designs. The 2N247 AF-amplifier is one more example of RCA’s extensive program for advanced products Push-pull Class B 2N109, 2N217 of the highest quality. sae a For your next high-frequency application, try the new RCA-2N247 DRIFT Transistor ge ving 20139, 2N218 available through your RCA Distributor. For technical data on the 2N247, write os RCA, Commercial Engineering, Section A-41-NN, Harrison, New Jersey. Wetan pant er
TR fi AY Ss i STO R Ss Class A RF-amplifier 2N247 *All are p-n-p germanium-alloy types, RADIO CORPORATION OF AMERICA hermetically sealed in insulated metal TMK (SI@ Semiconductor Division, Somerville, N. J. envelopes.
January, 1957 121
AMERICA’S FINEST VALUES IN “LOW COST” HIGH FIDELITY
wt.
CONOMY 20 WATT AMPLIFIER $22.95
NEW 1957 MODEL Push-Pull 6L6 Output Tubes Response 30-15,000 CPS Bass and Treble Tone Controls Input for Xtal or Dynamic Mike Input for Xtal or V.R. Phono With CU-14Y, 12” Coax Speaker. . With Pi5-CR, 15” Coax sage With Imperial IV System With UF. 33GE
. $32.95 mot 9.95
Model HF-20
With imperial VI
A tremendous High Fidelity amplifier vaiue. bass and treble boost by separate tone controls. Use changer having crystal or variable reluctance cartrid crystal or mamic microphone. 20 watts sagt oul > speaker or " be Ji” high.
tu : 2—6L6, 2 . 4 his is a ststrife, * value. ready high fidelity amplifier at less than ti a kit. Ship. wt. 17 Ibs. Mode! 20 watt Hi-Fi amplifier. McGee's sale price, $22.95.
HF-20,
IMPERIAL 30 WATT AMPLIFIER $29.9
NEW 1957 MODEL Push-Pull 6L6 Output Tubes Response 15-20,000 CPS Bass and Treble Tone Controls Compensated Gain for G.E. Cart. Input for Xtal or Dynamic Mike With CU-14Y, 12” Coax Speaker .$39.95 With Pi5-CR, 15” Coax Speaker. .$49.95 With Imperial 1V Speaker System. $46.95 With Imperial VI $55.95 With HF-33GE .
New 1957 mode! 7 tube Pee ~~ 30 watt High Fidelity audio amp! lifier, A y $29.9 Features a heavy 4 Ib., speciail: anne hi inverse feed-back; to 20,000 cps. atches s
Model IMP-30
LOW-BOY 3-WAY HI-Fi
into Hi-Fi speaker baffle with en- Mahogany Finish
SPEAKER SYSTEM closed back. All dimensions may vary slightly. Approximately 19” 3-1957 MODEL Hi-Fi SPEAKERS @ COMPLETE SYSTEMS WITH 4 SPEAKERS
for apartment size Hi-Fidelity. Avail- SALE PRICE Over-all height © ACOUSTICALLY LINED ENCLOSURES
able in blond or mahogany finish.
Extra value made possible by our
use of new TV cabinets. Converted $2995
Va and 231," wide.
Equipped with 15” coaxial speaker and a 6” mid-range speaker on one side for
augmented mid-range dispersion.
Stock # GM-416 Stock # GB-416 Biond Finish The new 1957 Hollywood, cei high fidelity speaker systems are expressly esvaned ae realistic reproduction
from your Hi-Fi amplifier or
ake $3. with any perial amplifiers or Espey FM- ‘AM chatple cheree in this
» $399 Paodel” ryt Hol- odes - = “rung $4995
” 20 oo
Mada 7 re Hol-
any finish enclosure. tures a 12” General Electric 6.8 oz. Ainico V_ magnet, aluminum voice coi! woofer, jus 6” mid-range and Built-in variable weeters. wilt-in variable brilliance L-C crossover net- work. Model H-4H, Ship. wor' Pp 3. SS ibs. Price $39.95. 35 lbs. sale price. $4 $44.9 9s. price, $ ——
McGEE'S NEW 1957 MODEL
) 25 WATT 12’ COAXIAL SPEAKER
%& 142 o7. G.E. 12” WOOFER— % 3/2” COAXIALLY SUSPENDED TWEETER—
% BUILT-IN CROSSOVER— ‘| §95 ; %& ALUMINUM VOICE COIL WOOFER— go pag all speaker vaiue. Features a A — wiectsle aa",
25 watt high fidelity coax 44 of. y= nico V woofer with aluminum voice coil and exponential, mold seamiess cone. The eeter is a Raye Oe . oz. Ainico V, speaker nna y av ae the high 3-4 response to 17, S00. cps. oe is electrically conn upper register of ues. On oC “i Png con ip. 4
GE-120XT, 12”
3OOXT, 12”
17,5 aker. ice, $14.9
: Ship. wt, 8 Ibe. Sale price, $14.95. NEW 1957—3-WAY HIGH FIDELITY
SPEAKER SYSTEM 12” ALNICO V WOOFER 6” MID-RANGE SPEAKER 5” CONE TYPE TWEETER L-C CROSSOVER NETWORK
95 LEATHERETTE CABINET ‘24
BRILLIANCE AND PRESENCE = CONTROLS
New, 1957 mode! ES-312, 3-way economy Hi-Fi speaker system. Complete with 12” woofer having a high efficien- cy Alnico V magnet, 6” gt speaker and 3° tweeter with special!
n
SALE PRICE
ra «Housed in *. leatherette axpinet 19” high, 20” wide and 20%2" Fhe 6” pine ive an overall height of 25”. a as ee grill cloth and e back Ay wires to connect to 7,000 cps. 10 watts. An ideal system for 40 Ibs. Suggested List
MODEL ES-312 Response 30-17,000 cps any 8 ohm output of Hi-Fi apartment
$40.00.
radio or amplifier. Response 30 Price
or recreation room. Modei zS-312, Ship. wt. sale Price only $ $24. 9s.
BAL
diagram. Ship. wt. 23 Iibs..
NEW IMPERIAL 24 WATT AMPLIFIER $39.95
PUSH-PULL EL-34 ENGLISH MADE MULLARD OUTPUT TUBES WILLIAMSON TYPE CIRCUIT RESPONSE 15-20,000 CPS With CU-14Y, 12” Coax Speaker. .$49.95 With P15-CR, 15” Coax Speaker. .$59.95 With Imperial 1V Speaker System. $56.95 Wie SP12125CR. . $65. o“ With Hpetrg- innit 20 Model IMP-34X
ith any Sale price, $39.9
ne IMPERIAL SPEAKER ; YsT a
Imperial IV
with 8” G.E.
High Fidelity Speaker
Modes MPERIAL IV, High fidelity speaker system with General Electric 8” oo ; hoe , x covered plyweed eab inet 10” x 10” x caeener Fay tie ih fide nity adi tf or aker or wi any i eli radio, ampli PERI RIAL IV contains a noha Electric Mode! 850 or 9770 Norelco 8 high fidelity 8” PM speaker with 6.8 oz. Alnico V and ee cone with 8 ohm voice coil and a S$” tweeter. Response SO to 15,000 cps. Model IV imperial $19.95. jl Mode! imperial vi. vered. i in appearance one i” WE Equipped we ¥ mate! oz. Ainico V magne us PM tor middie t connect to any pod Shidetity ‘amplifer. (8 ohms ion ial price, $29.95. i for use with HF-20 and IMP-
NEW 1957—5-WAY HI-FI SPEAKER SYSTEM ON BAFFLE BOARD Mode! 8-128, high fidelity 20 watt, SALE Sigg eg! PRICE
S-way speaker syste on an fle
d. Mas 12” G.&. 2—4x6"” mid-range 5s ” high-range and 3” ideal for use Completely wired, nv AE Cs Py 8 take
s all with Ailnico V magnets
° s. 10%
if eeeared with any radio ny cuigiien OR
he. wood, leatherette 3-way ie"the” Imperial wif , “except 4” taller
mper
crossover network with variable bril- liance conten’. Mount i cloth, 75¢
12” COAXIAL PM SPEAKER
RESPONSE 25-17,000 CPS.
89 5 | 12-V3Y, nigh. ef Mode! 12” coaxial
crossover oe Anny, oy ll con 5... ra) ae = lg AF.
eeter watts 17,000 cps, Shi yt 2 8° $17.00 1a-vav,, 32”, coaxial PM emgener.
13995
THEATER QuaLity HIGH FIDELITY SPEAKER SYSTEM 15” WOOFER PLUS—ELECTROVOICE MODEL 847 MID-HIGH RANGE SPEAKER — 600 CYCLE LC CROSSOVER. A theatre quality, powerful speaker system for ho roo! audio amplifier. ‘8 ohms
This speaker arrangement wii! connect to
Sa Features a 15” el: i juty hich is equal to a PM r with up to 10 Ibs i magn vepreawens the low audio
pepister from 600 cycies down cps. An Electro-Voice Model 847 horn type speaker
is used for the middie range and high yanee of suet. These s rs
nected to a 600 cycie .) oy sover twork,
the a exciter for the 15” ow could Spend over $100 for a speaker
tem and not beat this one. Stock No. EV-18847x, McGee's sale price, $39.95.
TELEPHONE VICTOR 2-5092 1903 McGEE ST., KANSAS CITY, MISSOURI
RADIO & TELEVISION NEWS
wit “ORDER SENT C.O
22 TUBE ESPEY FM-AM HI-FI TUNER-AMPLIFIER price *119%
A REGULAR $199.50 NET VALUE ages FOR $119.90
MODEL 700G FM-AM TUNER ONLY— SALE PRICE
MODEL 501G AMPLIFIER $49.95 SEPARATE
FM/AM TUNER ESPEY 24 WATT ESPEY 14-TUBE MODEL 700G MODEL 501G AMPLIFIER
“ESPEY DEAL—1A ok
Espey 7006 tuner with 24 watt amplifier plus VM-95 3 speed VM on
1 Mill Diamond $144.95 |
7 9” | | Sains BIOS
| $ | ESPEY DEAL—2 | 39% Ordered
| Espey 700G-S01G tuner with 24 watt with Tuner
OS2A cartridge. eee ee
ore offers you both the regular $119.50, ag tube Deluxe FM-AM tuner and the $79. sale pr of only $119.90. Th pe Sao 7006 Espey tuner has its own 10
vy
no tone contro Model 8 tube ultra linear p> al fideli io aw offered separately at the special sale price 5 ae amplifier features less than 1/2 percent distortion Noh high del letected by electrical instruments only. Chassis cirsult. ane. phase inverter and 2—SV4 | Pra gn a Ha ce
for $119.90. shipping wt., amplifier.
built in power ke at 6 db. Sy 240kc at 6db. Audio response flat from Chassis is 14” long, 81/2” high and 10”
tubes; tted case output Leg agi with ccoete ally made grain- is output transformer alone Js a $20. .95, or buy both the 700G tun id th $49.95 when pure he separately. Tuner rr ee the special deals Port the 700G-501G tuner-amplifier combination with record c for extra money saving svaines. Also, special discount on speakers and speaker systems when ordered with your Espey tuner and
new equipped with a GE bg . $164. 95 | supply. Performance es are:
| ESPEY DEAL—3 |
| Espey 700G-501G tuner with 24 watt amplifier plus Garrard RC-98 equipped
with a GE RPX-OS2A car- $194 95
amplifier plus 456 Collaro changer SO value 8 tube audio amplifier for the featur Pa
tridge. Ne
| Order any of the following epenhers with your Espey tuner and amplifier:
12” coaxial PM, CU- 14¥-$10.00 extra
1S” coaxial PM, P1S-CR—$20.00 extra
Imperial tV system—$15. rin
Imperial Vi system—$25.0:
Norelco 9762—12” Rowe cod $59.50 at
$30.00 extra.
1 EV84—15W system—$150.00 extra.
c 4—6V6GT in push- pull Williamson |
Hh
00 value e ha | Amplifier
BUY YOUR AUTOMATIC CHANGER AT McGEE
AND
WEBCOR GARRARD SAVE 456 - $34.50 1642-1 RC-98 4-SPEED COLLARO ag oe eee ee
ically and manually. Itnter- ~nlnee records of the same speed and shuts off after last A of idier wheels eliminates All of the oe features of sna Collaro 4 omatic record ¢
COLLARO
34.5) sapphire and rt mil diamond stylus, Sale price, $46.95
} 9 ogg ol age OP popular 3 speed changer on metal base with ceramic crystal cartridge, ale price, -
Webcor 1 siczi> 3 speed changer, less base with RPX-OSO G.E. VR cartridge, $27.95. No. 1914, large 45 RPM spindle for 1641 and 1642 Webcor changers, $2.44 extra Webcor “ert p1- 27, Hi-Fi chrome Gna with 2-separate plug-in cartridge shells, less cartridge, base, ‘Sale price, $3
Webcor GR-1631-27, same as ag ‘ana with G.£. RPX-OS2A cartridge with 1 mil dia- mond stylus, Sale price, $49.
Webcor CR- 1631- 21, Hi-Fi chrome changer same as above except has one piece tone arm with RPX-OS2A Golden Treasure cartridge, 1 mil diamond stylus, Sale ore $47.95. No. 1915, large 45RPM spindle for 1631 series Webcor changer, $2.44 ra. Precut mounting board for 1641 or 1631 series Webcor changer, $1.96 extra,
changer, ures ever ve
New 1957 Garrard Model RC9B, -*‘crown 11," 3-speed putometic one of the world’s finest. Provides found in an automatic changer. anger, ige—S6 1 mil diamond and 3 mil sapphire meodion, RPX- OSaA $82.1 10. indie on ees extr,
88 iumph"’ mode! with most of the a of the 98. RC8S, less car- tridge-$53. 41. with RPX-052A cartridge as above—$69. GOLDRING V. R. CARTRIDGE WITH 2 SAPPHIRE STYLII $5.95 WITH 1 MIL DIAMOND, 3 MIL SAPH. $13.95
McGee offers the internationally famous Goldring variable reluctance phono cartridge, who want the finest and most
super
6.1 s. Large 45 rpm,
ain and compensation are equipment with sa $5.95. For
accura (input standar at M
$5.95. No. 0546-Ds, ‘Goldring Vv.R. $13.95. 1 mil diamond stylus for
$7?
2 for $15.00
(w ' Gelatinn * vid R. 9.95
Sa
ge, purenasea od seperately,
8” NORELCO P14 Specially Priced at $7.95 for sale ad,
cps y 11,000 Gauss. Powerful
Pp. Ainico Magnet. A to your Hi-Fi speaker col-
lection.
12" NORELCO 9760 HI-FI SPEAKER $19.95
PM speaker. Has a 15.8
North American Phillips Bog cord cone. 8 ohm auss. ideal for use 3 peaker. prior "the
price only $305
the large pong
uss me jodel 9762, 12”
WRITE FOR McGEE'S 88-PAGE 1957 CATALOG NEW 8 TUBE 6 VOLT PUSH-BUTTON MODEL $37.95
notes Hi-Fi speaker, Sale
McGEE RADIO COMPANY
January, 1957
PRICES F.OB SEND 25° REMITTANCE WITH
McGee’s Famous 12 AND 15 INCH COAXIAL P.M. HIGH FIDELITY SPEAKERS
1295 oy
12-inch 5-Inch Model CU-14Y Model P15-CR
Response from 30 to 17,500 Special mae ty luspended Built-in crossover network. O to to 3.2 to 8 ohm output. Don't coatuse this. ceeaiear
is a fine quality speaker. ke
+2. ° non. ty aker. Response down 20 cps. and up aits oz. Vv magnet in the 15” woofer. Seciatiy — coaxially’ cuapennee vy: high TB got —, Built-in crossover network. Matches 3.2 to 8 ohm output pratima ads A regular sea. "3b Tee
-9 1S” woofer has 6.8 oz. Ainico V magnet. . Only two wires to connect any 8 ohm 0 to 15,000 cps. Model No. M15-CR, 15”
12” pigh fidelity coa: PM speaker. » haa BS. met in the 12” woo ter.
ier. Frequency response ou pe, coax. om speaker, Sale price, $16.95.
FAMOUS STANDARD ‘COIL CASCODE TUNERS
tuners SALE PRICE
2 This tuner will, give the o itode ay Fall cascode mode vai nee 4%" shaft le low $12. red.
or
ndous ravchine makes * price “possible.” Lge? sha No. TV-20) - Sale price
2: Matching knobs for Standard Coil tuners. Set No. SCK-2 for fine tuning and channel selector, Set VCK-2, matching volume and contrast knobs. Either set only S9¢ a pair.
pera COIL PENTODE TUNERS $7. 95
“eavier in mi just veslaee cut to desired length. with h 204" 3 *, length of shaft. Sale price,
2 FOR $25.00
ai" or 41” shaft. Matched knob” set 59¢ extra
awortine 21MC OR 41MC $1.95 SARKES- . TT-3A, 2 the Serine on 28 channel TARZIAN | TUNER
tune he Available $7.95 ea.,
for one With tubes, $7
2 tube Sarkes-Tarzian 41 me tuner with tubes 44" Smatiiest cascode tum yg
many sets. $7.95 we 2 for $ of the above tuners with 9
-00 extr
Type 3, 3 tube a3 me Sovine 1 Tarzian tuner with Rotary switch type complete sca HG ai S tu al Neer om new low price of to Use — either
"het, $4.95
Y: =
n fine tuning. shaft.
276”
RCA KRK-12 TV TUNER Brand New—with Tubes
CA Model KRK-12, UHF-VHF TV tuner SALE PRICE
rR with tubes: 2—68Q7A, GAF4 and 684. A
complete tuner with all 12 VHF strips, but 2 for $13.00
with blank strips in the UHF positions. This tuner fits many RCA sets using 40 megacycie 1.F's. 270382 also KCS-66, etc. Original tuner list was about $50.00. We offer them new at abo
tubes. Ship. wt. 10
price, $6.95 each, 2 for $13.00.
WITH CRYSTAL MICROPHONE SALE PRICE $9.95
mode! MCL-E3 miniature received on any bro a radio station.
micro — and nect, ecord rd player:
Shin wt. 4 Ibs. Net
KANSAS CITY OR
TELEPHONE VICTOR 2-5092 1903 McGEE ST., KANSAS CITY, MISSOURI
uit ORDER L SENT COD
BUILD 16 RADIO CIRCUITS AT HOME , 998
With the New DELUXE 1957 Progressive Radio “Edu-Kit” only
Now Includes * Transmitter
* Signal Tracer
* Signal Injector * Code Oscillator
@ No Knowledge of Radio Necessary
@ No Additional Parts © or Tools Needed
@ Excellent Back- round for TV
@ Unconditional Money- Back Guarantee
Tool Set, Pliers~ Cutters, ~~ Sol- | FREE dering Iron, t Too
WHAT THE “EDU-KIT™ OFFERS YOU
The 1957 “Edu-Kit” offers you an outstanding PRACTICAL HOME RADIO COURSE at a rock-bot- tom price. You will learn radio theory, construction
ing regular professional manner; how to service and trouble-shoot radios. You will learn how to work with punched metal chassis as well as the new Printed Circuit chassis. You will learn the principles of RF and amplifiers and oscillators, tectors, rectifiers, test equipment. practice code, using . You will build 16 Receiver, Lg arog Code Oscillator, Signal Tracer and Signal Injector circuits, and learn how to oper- 4 them. You will receive an excellent background for TV. In brief, you will receive a basic education in Electronics and Radio, worth many times the small price you pay, only $22.95 complete.
PROGRESSIVE THE KIT FOR TEACHING METHOD EVERYONE
The Progressive Radio 7 “Edu-Kit” is the fore- ss oe — = most educational radio kit in the world, and is universally accepted as the standard in the field of electronics training. The “‘Edu-Kit’’ uses the modern ga prin- ciple of “‘Learn by ing.”’ You begin 4, ‘build- — — radio. Grad- ually, in a progressive mentee, and - J own on ae eee — rate, you construct more
ee ates on any voltage from advanced multi-tube ra- 105 to 125 volts, AC and Dc. For use in countries employing higher line & professional radio tech- | voltages, a 210-250 Volt nician AC/DC model is availiable.
THE “EDU-KIT" IS COMPLETE
all parts and instructions neces-
ran’
tubes, tube sockets, variable, electrolytic and paper
dielectric condensers, resistors, tie strips, coils, hard- > 4 punched metal ci
sold iron, an Radio and Electronics Tester. includes
instructions and
Oscillator. You will also receive lesvoms for servicing
with the Progressive Signal Tracer and Progres
sive Signal Injector. @ High Fidelity Guide. FC FCC
Amateur License Training = Quis Book. ae parts, components, etc. of the * ‘Bau. Kit” 00% unconditionally guaranteed, brand new, ~-g
tulle selected, tested and matched. Everything is
— to keep. The complete price of this practical
home Radio and Electronics course is only $22.95.
TROUBLE-SHOOTING LESSONS
You will learn to trou- J. Stasaitis, of 25 l’op- ble-shoot and service ra- | lar P)., Waterbury, Conn., dios, using the profes- | writes: “I have repaired sional Signal Tracer, the | several sets for my friends, unique Signal Injector,| and made money. The and the dynamic Radio| ‘‘Edu-Kit’ paid for it- and Electronics Tester. | self. I was ready to spend Our Consultation Service | $240 for a course, but I will help you with any | found your ad and sent technical problems for vour kit.
FREE EXTRAS
s Set of Tools « Radio Book « Radio and
Se mateur License Training « Printed Circuitry DAY UNCONDITIONAL MONEY-BACK GUARANTEE— ORDER FROM AD—RECEIVE FREE BONUS RESISTOR & CONDENSER KITS WORTH ben
eine tes ‘mation valuable Radio 4 — on. U.S.A.—No . j= Wit? on oo ay DC $23.95; 210-250 V. AC/DC $26.4:
PROGRESSIVE wei -KATS* i inc. oe teen, Sve: Bopt. OCs, Sverre, 8. Ys
124
FRVICE associations that are carry-
ing out aggressive campaigns against the extension of captive service are deeply conscious of the skeleton in their own closet—the unethical service shop. Although unethical operators represent a very small minority of the independent service shops, their mach- inations have been responsible for most of the bad publicity that continues to hurt the TV industry in many ways.
Unfortunately, the complexity of TV circuitry makes it easy for a larceny- minded technician to bilk customers for a comparatively long time before his activities are brought to light. The most flagrant violators of all codes of business ethics, of course, are the gyps who thrive on pulling sets to their shops. Their charges for even the sim- plest shop jobs are based on “all the traffic will bear.”
The activities of these consciousless crooks quickly come to the attention of the local Better Business Bureaus. Ridding the industry of them has been a frustrating experience to both the BBB’s and the legitimate service shop operators who are constantly trying to clean up their own industry.
The cagiest, most larcenous charac- ters in the service business are the re- placement tube racketeers. A case in point is a service business in a large eastern city operated by technically untrained individuals. These men have developed a “racket” that will pay off for them as long as they can find un- scrupulous technicians who will do their bidding.
In this racket, home TV service is promoted at $4 per house call. How- ever, the customer actually pays $7 per call, since the $4 is listed on the service order as charges for the “serv- ice call” and the customer pays an ad- ditional $3 for “technical labor.” Tech- nicians who work for this outfit are paid good wages—but they are re- quired to sell a minimum of $12 worth
‘of tubes on each call. Sooner or later,
in one way or another, set owners learn how they have been taken in cases like this one. It creates a resent- ment against all independent TV serv- ice businesses.
One angle on how this bad publicity hurts all ethically operated service shops is shown in the continual “beat- ing” that field service technicians get from set owners. The unjustifiable and unreasoned complaints and sarcastic criticism over TV service has driven many excellent technicians out of the consumer service field and into other activities of the electronics business.
A prime example of how utterly ab- surd some of these complaints are was
recently brought to the attention of your editor during a visit to a large shop in an eastern city. A very irate man called this business to “lay them out” because one of their service tech- nicians insulted his wife. He claimed the technician had forced his wife to borrow money from a neighbor to pay for a TV service call. Although none of the office personnel knew the cir- cumstances surrounding the call, the set owner used up more than thirty minutes of the time of three people, in- cluding the shop owner, with blistering comments about the discourtesies and crooked dealings of TV service shops.
When the technician reported in, the shop owner asked him about what hap- pened when he made the service call. The technician was surprised to learn that any difficulty had arisen at all. When he presented the bill for pay- ment, he said, the wife explained that her husband had taken the family check book with him and she would have to borrow a blank check from her neighbor. On a follow-up call to the home, the wife apologized to the shop owner for the behavior of her husband.
Similar experiences with suspicious or downright unreasonable people are the daily lot of the thousands of com- petent, honest, hard-working techni- cians who have elected to make a ca- reer out of electronic service work. These occurrences are driving many good men out of the service field, par- ticularly since there are so many at- tractive jobs open in factories and other aspects of electronic work, in- cluding defense projects.
Unity in Philadelphia
Recently the five service associations in the Philadelphia area met to discuss the feasibility of forming a single or- ganization in that area for the service industry which could represent all ele- ments including the service dealers, contractors, and technicians. The as- sociations involved in the discussion were the Television Service Dealers Association, the Northeast Television Dealers Association, Allied Television Technicians Association of New Jersey, the Television Service Dealers Associa- tion of Delaware County and the Phila- delphia Radio Servicemen’s Associa- tion.
The members of these several groups agreed they would have to find some organizational pattern that would permit the service industry as a whole to cope with such problems as captive service, increased operating costs, loss of technicians to set and electronic manufacturers, and curbing the activi- ties of unethical shops.
The group felt that set producers, including those with service organiza- tions, must realize their responsibility to those in independent service who have worked shoulder-to-shoulder with the manufacturer in establishing TV as a must in practically every home. They were also of the opinion that other elements of the industry should study and understand the load the in- dependent service industry is carrying and provide the shop operator with fi-
RADIO & TELEVISION NEWS
ciatis
Lice: A
and | to th unde Tele the ( ciatic draft CSE. ment sion, bersl will | ture
Janu
nancial aid and assistance in running his business profitably.
Promotion for Service Fair
The Indiana Electronic Service As- sociation is moving forward rapidly with plans for their full-fledged Elec- tronic Service Clinic and Fair to be held in Indianapolis during April 1957. The JESA is a state-wide organization composed of practically all local serv- ice associations now operating in Indi- ana. One of their major projects is to develop interest among dealers and service operators in sponsoring a li- censing bill to be presented to the In- diana State Legislature.
The promotion and management of the mid-west Electronic Service Clinic has been turned over to a professional public relations and sales promotion organization called Plans Incorporated, which is headed by Edward J. Lanigan.
PR Man Engaged
The Radio Television Guild of Long Island recently engaged Richard T. Guidera, a professional public relations counsellor, to fill the post of executive secretary for the association. Mr. Gui- dera, a graduate of Harvard College, is an ex-marine who handled Marine Corps public relations in the metro- politan New York area for three years. In commenting on the duties of the newly appointed executive secretary, the Guild News said:
“The duties of the executive secre- tary will be to assist officers of the Guild with the association’s adminis- tration, add continuity to the many programs conducted each year by the Guild for the membership, assist the editors of the Guild News, and work with the Distributors’ Shopping Com- mittee.
“Also included in the duties of the new office is the task of working to in- crease membership of the RTG of LI and thereby give it added strength and position within the Long Island com- munity. This latest assignment is tied directly with the added duty of public relations director for the Guild and the coming program to increase patronage of member shops by the general public of Long Island.”
The RTG of Long Island, which re- cently held its first and highly success- ful Long Island Electronic Fair and Clinic, is one of the industry’s largest and most successful local service asso- ciations.
Licensing Bill Proposed
A bill to license service technicians and dealers, intended for presentation to the California State Legislature, is under study by members of the Radio Television Technicians Association and the California State Electronics Asso- ciation. Individual copies of the first draft of the bill were mailed out to CSEA and RTTA members for com- ment and consideration. A final ver- sion, mutually acceptable to the mem- bership of the organizations involved, will be proposed jointly to the legisla- ture for enactment. —30-
January, 1957
ON ONE COMPACT CHASSIS! FISHER FM-AM TUNER, AUDIO CONTROL AND 30-WATT AMPLIFIER!
EVERYTHING YOU NEED! ON ONE SUPERB CHASSISI
THE
FISHER
“BOO”
HOUSANDS have asked us for it— and here it is! An extreme- cena FM-AM tuner, a powerful 30-watt amplifier, and a Master Audio Control — all built on one compact chassis. Simply add a record changer and loudspeaker to the FISHER “500” and, as easily as that, you have a complete high fidelity system. Its quality — in the finest FISHER tradition. Its appearance — the timeless beauty of classic simplicity. Here is the most economical form in which you
can own FISHER equipment. Chassis Only, $239.50 Mahogany or Blonde Cabinet, $19.95
Outstanding Features of THE FISHER ‘‘500’’
= Extreme sensitivity on FM and AM. Meter for micro-accurate tuning. § Full wide-band FM detector for maximum capture ratio. ® Powerful, 30-watt ampli- fier; handles 60-watt peaks. @ Uniform response, 16 to 32,000 cycles. @ 4 inputs, including separate tape playback preamp-equalizer. ® 4, 8 and 16-ohm outputs match all existing speakers, ® Recorder output ahead of volume and tone con- trols. & 7 Controls, including 9-position Channel Selector (AM, FM, AES, RIAA, LP, NAB, TAPE, AUX 1 and AUX 2), Loudness Contour (4-position), Vol- ume, Bass, Treble, AC-Power, Station Selector. & Beautiful, die-cast, brushed brass escutcheon and control panel. & Pin-point, channel indicator lights. * Smooth, flywheel tuning. = Largest, easy-to-read, slide-rule dial, with logging scale. &@ High efficiency FM and AM antennas supplied. @ 14 tubes plus 2 matched germanium diodes. ® size: 13 7/16” w. x 12%” d. (excluding knobs) x 6%” high.
Prices Slightly Higher In The Far West
WRITE TODAY FOR COMPLETE SPECIFICATIONS FISHER RADIO CORP., 21-23 44th DRIVE + L. I. CITY 1 > N.Y.
MEASUREMENTS CORP. SIGNAL GEN. MODEL 78B
Gov't. Avg. Cost $300.00 Used for alignment of radio L.F. freq. stages of ae receivers and other test operations requiring .W. or modulated R.F. voltages. 15 to 25 Mc ond 195 to 225 Me signal may be unmodulated or ap at approx. 30% by an audio fre- quency of 400 or 8200 CPF. 0 Brand New.......secseecees 3% Used Exc. .... -.++..$29.50
COMMAND ARC-5 TRANSMITTER
T-20...4%05.3MC New 7-21. ..5.3 to 7 MC
Used ..
Excellent sis: 9s 7.95
RECEIVERS 190-550 KC 1.5-3.0 MC
RCA MOBILE RECEIVER 80-41 mc. AM Crystal Controlled.
each. DYNAMOTOR FOR ABOVE 6V DC Input-250 V DC Output. $6.95 each. RCA MOBILE TRANSMITT . AM Crystal Controlled. $14.95
DYNAMOTOR FOR ABOVE ae -375 Volts 250 ma Output.
$14.95
6V DC $9.95 e
ALL £5 ‘ABOVE USED UNITS $39.50 FM WOBULATOR CAPACITOR
Frequency modulation unit with a permanent magnetic field and a moving coil mechanism driving a metal diaphragm supported at the rim. This diaphragm sets as a moving plate of the frequency modulator ca- pacitor. W/ instructions. Bulld TV sw sig. gen. 2 for only .
: Sweet Oscilloscope Deals INDICATOR UNIT. For conversion to test scope, panadapter, analyzer, etc. Double deck chassis. 5CP1 mounted in tube shield, Less small tubes and crystal, but complete with 6CP1. $9. 95
adar indicator Unit: Yor co conversion to test “scope or for use as modulation monitor. Has standard test-scope CR tube, H Cent, V Cent, Bril, Foc, Gain, and range selection switch. Ex- ternal power source was used. Tubes: $9. 95 4-6AC7, 3-6H6, Less 1-5BP1. New.
BC929 RADAR, $9.95
BC-929 A Radar Indicator Scoop. This unit could be rebuilt into a fine test scope. It is an ideal size. 8x9x14 priced with tubes 2—6SN7, 2— 6H6, 6G5, 6X5 and 2X2. This is a red hot Le 4 Scoop Price. New $9.95
FINE QUALITY NAVIGATIONAL EQUIPMENT
Determine exact geographic poses of your boat or plane! Complete, BRAND NE installation consists of: 1D-6B/APN-4 Indicator; R-9B/APN-4 Receiver; PE-206 Inverter; Set of Plugs; Visor for Indicator; Operation ee $i 29 50 Brand New, Export packe . IDGB INDICATOR, ROS RECEIVER, Excellent 5 $69. 50 UHF TRANSCEIVER, APG-5 2500 Mc complete with 2C43, 2C40, 8E29, 1B27, VR105, 6Y3, 6AL5, 2 each g 2X2 and 8 each GAKS............ bd PE1O9 INVERTER
12VDC input, 115 VAC, 142 amp, "$3 phase,
400 cycle output. Brand New xc. use
$45.00 HI-Fi Headset for only $7.95
Uses annular grooved plastic fibre comes with voice coils as in speakers, and brand new chamois eur pads to obtain spacing for correct acoustical load. GIVES FINEST MUSIC REPRODUCTIONS! Irap.: 800 Ohms per unit or 600 Ohms when wire series.
USED. EXC. COND. WITH BRAND NEW CHAMOIS CUSHIONS
APG 5 or 15 CAVITY 10 Cm. 2C43 ose Xmitter, 2C40 Loc. Ose. Rec. 1827 TR; tunes 2400 to 3000 MCS, less ee.
Radio Receiver 11-tube UHF tunable 234-258 MC receiver with schematic
Complete with tubes. 8 ea. of 6AK5, $6 95 7 ea. of 9001, 1 ea. of 12A6, Like new s Less Tubes x
SCOPE TUBES $ he . 4 for $7
DYNAMOTORS
Type Input Output Excellent New BN-77 12 VDC 1000 VDC 350 MA $14.95
BD-83 12 VDC 375-150 MA 1.95
DM-35 12 VDC 625 VDC 225 MA 9.95 19.95 DM-37 24 VDC 625 VDC 225 MA 6.95 9.95 DM-64 12 VDC 275 VDC 150 MA 3.98 5.95 DM-34 12 VDC 220 V 80 MA.... 2.95 4.95 DM-65 12 VDC 440 VDC 400 MA. 14.95 19.95 DA-1A 24 VDC 230 VDC 100 MA. 4.95 DM-28 24 VDC 230 VDC 100 MA. 4.95 DM-32A2 12 VDC 250 VDC 60 MA 4.95 MOBILE HEAVY DUTY DYNAMOTOR: 14 V. IN- PUT-output: 1030 VDC 260 MA. Tapped 515 V. 215 MA. use or 6 V DC INPUT-500 V. 175 MA. While they last—-DM-42-Excel. Condition. $4.95 Brand $9.9
MG-149F were 115AC, 400 cycles,
Exc.
RS-38 Navy Carbon Hand Mike.
Bh. « chile neSo.0 6 ees ctw tse 46 $2.45 ea. 1-96A Signal Generator 100-156 Mc, com- plete w/cords and cables, like
new
Variac General Radio—Model 200 BO-130V, 1 Amp. Brand new $5.95 ea.
24 vVpc mou.
MN-26-C—Remote Control Navigational Direction finder and communication receiver. Manual DF in any one of three freq. bands, 150 to 1500 KC. 24V. Self contained dynamotor supply. Complete installation, including receiver, control box, loop, azimuth control, Left-Right Indicator, plugs, loop transmission line and flex. shafts, oper. & main. manual. Ideal for use in boats, etc.
BRAND NEW
MN-20-E Loop MN-52-CRANK Drive. New MN-28-C
DYNAMOTORS for above, 12VDC, MN-26 9. 95
METER—3”-0-5 Ma. 270° Indication—By Pass Shunt and add scale. Excellent Condition Five for
WRITE FOR NEW BULLETIN ALL ITEMS F.0.B. CHICAGO 25° Deposit required with orders
R W ELECTRONICS *”
N 2430 S. Michigan Ave. Chicago (6, Ill. PHONE: CAlumet 5-1281-2-3
ZYTRON QUALITY BRAND
RADIO & TV RECEIVING
TUBES
INDIVIDUALLY BOXED Terrifically LOW PRICED! Send TODAY for Complete Catalog
ZYTRON TUBE COMPANY
220 West 42nd Street - New York 36,N.Y
JENSEN COMMUNICATION SPEAKER
Mounted in —— crackle-finish metal case, Heavy duty. Approx, 6x8”. Can be used in hi-fi setup. Like new, with 300 ohm matching
transformer ... : ®
Son-saa TRANSCEIVER For 2 and 6 meter. $29.95
ASB RECEIVER For 420 MC operation, New, bo:
$19.95
THIS MONTH’S SPECIAL
0-1 MILLIAMP = es indication. Just by- pass shunt and add 1 Used, good <uitiien, .
NEW CATALOGUE NO. 110 IS OFF THE PRESS! Get your free copy today!
J. J. GLASS ELECTRONICS CO. 1615 S. Main St. Los Angeles 15, Calif.
NEW TV ANTENNA Davis Electronics, 4002 W. Burbank Blvd., Burbank, Calif., has just intro- duced a new all v.hf. TV antenna called “The Bandmaster.” It is claimed that this antenna has a voltage stand-
ing wave ratio which is uniformly less than 1.6 to 1 on all v.h.f. channels. This antenna is a 10-element all- channel yagi type. Elements are com- pletely pre-assembled at the factory.
PLANT EXPANSION
Alliance Mfg. Co., Inc., Alliance, Ohio, subsidiary of Consolidated Elec- tronics Industries, has announced the lease, with option to buy, of three buildings formerly occupied by McCas- key Register Co. The addition of this space, approximately 81,000 square feet, will make it possible for the com- pany to acquire additional products.
INDOOR ANTENNA
Snyder Manufacturing Company, Philadelphia, Penna., has added a model to its line of indoor “Directron- ic” antennas. To the conventional con- figuration of the indoor rabbit-ear de- sign, the manufacturer has added crossed circular phasing elements in the “Picasso.” This addition is said to improve rejection of ghosts and snow. The phasing bars and adjustable side elements are made of shiny brass and are mounted on a heavy tip-proof base.
On the latter is mounted the “Direc- tronic” selector to permit optimum ad- justment for each channel.
Ben Snyder, head of the company, is now in Europe on a one-month tour
RADIO & TELEVISION NEWS
with the purpose of discussing mutual arrangements with manufacturers on the continent. He hopes to market his company’s products through these for- eign organizations while the Snyder organization in this country handles distribution-in the Western hemisphere of products made by European com- panies. HELICAL COLOR ANTENNA
JFD Manufacturing Company, Inc., 6101 16th Ave., Brooklyn, N. Y., has designed an antenna to meet the grow- ing need for efficient low-band v.h.f. performance. This unit, the ‘‘Wonder- Helix Color-tenna,” is intended to make up for the deficiency in many fringe-area antennas currently in use, where maximum gain is achieved on
the high band, but only moderate-to- good response on the low band.
A pair of double-driven folded di- poles are phased for maximum signal
addition on the low band. A reflector, director, and deflector flatten, the bandpass characteristic. A 5-turn flat- plane helix provides high narrow-lobe gain on the high band. Gain is reported greater than that of a double-driven 5-element broadband yagi with a front- back ratio of better than 10 to 1 on low-band channels and up to 14 to 1 on the high band.
Also featured are all-aluminum boom-braced construction to withstand ice loading and heavy winds, good 300- ohm match, and uniform response to meet the requirements of color re- ception.
NATIONAL SALES CONFERENCE
Winegard Company, Burlington, Iowa, successfully completed its first national sales conference this fall. All selling representatives were brought together in Burlington for the intro- duction of the new 1957 line and dis- cussion of the recently launched ad campaign. The first day of the 3-day convention was devoted to technical sessions on the performance of the various models.
LARGER QUARTERS
Video Industries Company, 242 Mad- ison Ave., Port Chester, N. Y., manu- facturer of “Stacked-V” and “VICO” antennas for TV, has moved to a larger building. New facilities at the above address consist of 5000 ft. of manufac- turing space on one floor plus 2200 ft.
of storage space. Former location was at Jane St. and Palmer Pl. in the same city.
ROTATOR CONTROL Crown Control Company, Inc., New Bremen, Ohio, has aimed for greater eye appeal in the new 1957 version of
its CAR6B “Tenn-A-Liner,” antenna rotator control unit. To blend with either blonde or dark interior furni- ture, the “Tenn-A-Liner” case is fin- ished in beige and brown, with the former color predominating. A new dial offers greater readability, with positive directional indication, even when the motor is not operating. Fin- ger-tip operation and positive braking to prevent windmilling are other fea- tures provided.
COYNE QUALITY
Home Training at Untelievally Lou Cost
The future is YOURS in TELEVISION! A fabulous field—good pay—fascinating work—a prosperous future in a good job, or independence in your own business!
and full details,
including easy
Payment Plan. No
obligation, no FA
salesman will call. CP EN PO RIES o. cCOYNe
COYNE Television = [eee
| Home Training Division
| 500 S. Paulina St., Chicago 12, Ill.
| Dept. 17-HT5
| Send Free Book and details on how I can get
| Coyne Quality Television Home Training at
| low cost and easy terms.
Coyne brings you MODERN-QUALITY Television Home Train- ing; training designed to meet Coyne standards at truly lowest cost —you pay for training only—no costly ‘“‘put together kits.”” Not an old Radio Course with Television ‘‘tacked on.”’ Here is MODERN TELEVISION TRAINING including Radio, UHF and Color Tv. No Radio background or previous experience needed. Personal guidance by Coyne Staff. Practical Job Guides to show you how to do actual servicing jobs — make money early in course. Free Life- time Employment Service to Graduates.
ae B. W. COOKE, Jr., » President ELECTRICAL SCHOOL ial
A TECHNICAL TRADE INSTITUTE OPERATED é NOT FOR PROFIT
500 S. Paulina Street, Chicago 12, Dept. 17-HT5
| | Name.
we I Address. Coyne—the Institution behind this train- | ing ... the largest, oldest, best equipped | "
! City.
residential school of itskind. Founded 1899.
January, 1957
NAL IN COMPLETELY WIRED
| GUL Re ee
ei ee LAFAYETTE SIGNAL GENERATOR
NEVER BEFORE HAS A COMPLETELY WIRED AND TESTED INSTRUMENT OF SUCH ACCURACY AND QUALITY METER BEEN OFFERED AT SUCH A PRICE! 1% PRECISION
@ FREQUENCY 120 KC TO 260 MC RESISTORS @ 120 KC TO 130 MC ON FUNDAMENTALS SILVER CONTACT e@ LABORATORY ACCURACY AND QUALITY SELECTOR SWITCH A completely wired and tested instrument not to be confused with units sold in kit form at almost the same price, but with FUL a quality and accuracy of instruments 3 to 4 times its price. L SCALE RANGES Six overlapping ranges generate signals of 120KC — 320KC, oc Vv 820KC—1000KC, 1MC—3.2MC—11MC, 11MC—38MC and ; 37MC—130MC all on fundamentals with calibrated harmonics from 120MC to 260MC. Selector switch gives instant choice of ranges. Switch gives choice of internal modulation of 4 CPS or use of any external source at other frequencies, For audio testing the 400 cycle signal can be used separately. Outputs are unmodulated RF, modulated RF and 400 CPS audio. RF output is in excess of 100,000 microvolts and jacks are provided for choice of either high or low RF output. Stability is insured by special circuit design. Has a fine adjustment RF control. AF output is 2-3 volts, AF input is 4 volts across 1 megohm. Large clea: 5 inch etched dial plate and pointer are protected by transparent plastic bezel. Common AF terminals for EXT-MOD input and INT-AF for audio tests eliminate need put Ranges: for speciai AF output connectors. Machine engraved panel lettering. Handsome gray metal case with 500; 0- 1000 carrying handle. Measures 61/2” x 10” x 41/2”. Comes complete with pair of leads. AC line cord its and plug. Operates on 105-125V 50-60 cycle LAFAYETTE LSG-10 SIGNAL GENERATOR .. * ee R B : This Multite America! A very itester is a complete
pEW! LAFAYETTE CAPACITOR-RESISTANCE TESTER |uaeeran
2,000 ohm
COMPLETELY WIRED AND TESTED
wok COMPLETELY WIRED AND TESTED + 2 ront panel, © CHECKS ALL TYPES OF CONDENSERS FOR range requirce 1p so agelt_ AC First capa- Bi. SO SAPAGITy, Leannoe, oven soars OR Complete with test ieaae ne . INTERMITTENT CONDITION 4 Ibs. leads 4 © DIRECT READING SCALES FROM .00001 RW-27A ow YO 1000 MFD AND 100 TO 5 MEGOHMS —— =
A stable and accurate bridge ty o civouls sengnures yyy ~
4 ranges of .00001-.005 MFD, .001 to .56 MFD, .1 to 50! an
20 101000 MFD. Two posiesance renaes of 300-56.900 ont 0,- oo Sp Ae 20,000 OHM
000 to 5 megohms, Check leakage under actual load with choice
of os 150, 55), 9 or = on by aeeeator eons LT DC aoe OHM PER
Power factor control from to § %. Checks for leakage, open,
short, or intermittent operation. All readings taken directly off Cc MULTITESTER
scales after setting magic eye to maximum. Completely self-con- Attractively finished steel case with rounded
Operates from 110V AC. Size 934"L x
.NET 21.50
4 AND 6 TRANSISTOR SUPERHET KITS POCKET AND HOME RADIOS
FOR: SPEAKER AND EARPHONE OPERATION
4. « 3-5°16 W x 1 O BUILT-IN ANTENNA! REQUIRES NO EXTERNAL ANTENNA OR GROUND
2-TRANSISTOR PUSH-PULL OUTPUT KIT WITH SELF-CONTAINED SPEAKER IN PLASTIC CASE
Converts 4-Transistor Kit KT-94 into a 6-transistor home radio with spesker. Transitorized push-pull audio stage plugs into 4-transistor kit, suitable for group listening. Performance equal or superior to commercially wired sets selling at much Bite pM spe — ees co age om?
M speaker, pre-punc chassis, speaker case (holds The , . : . all components), battery, hardware, instructions and diagrams. tivity Muhitentes tee eneeenn,
a pangs Net 11.50 ¥ instrument (not a kit), In ad- 96 dition to its unusual sensitivity
NSISTOR PUSH-PULL OUTPUT KIT WITH SPEAKER of 20,000 OHMS PER V
‘“\~ = Completely self ined, pocket size portable set which oper- ates a miniature earpiece so only you can hear, The circuit uses 4 transistors (2 high frequency and 2 audio) plus a ger- manium diode, 2 IF stages and built-in high gain ferrite core and antenna, The result is a sensitive, stable and selective receiver covering the entire broadcast band. it requires no outside antenna or ground connection. The kit is supplied com- plete with transistors and all parts, including battery, and A.C., for drilled end punched chassis. Pictorial and circuit diagrams V A.C. Attrac- are included with simple, easy-to-follow instructions. (Note: b 1 metal bottom. Size 61/4"x41/4"x21/2", Earpiece and carrying case are not supplied.) RW-30A batteries and leads. Shipping weight 41/> Ibs. KT-94 --Complete Kit. Shpg. wt., 2° lbs serseeeesererceceessssatesessseeree--. Sin@ly, Each 19.95 MS-311--Leather Carrying Case In lots of 3, Each 19.25
MS-260—-Super Power Dynamic Earpiece
PROFESSIONAL TRANSCRIPTION TURNTABLE AND VISCOUS-DAMPED TONE ARM
THE FINEST TRANSCRIPTION TURNTABLE AND TONE ARM FOR THE PROFESSIONAL USER AND THE AUDIOPHILE
PK-100A ANSCRIPTION TURNTABLE
New 3-speed instrument with built-in stroboscope and viewer for exact speed determination, and magnetic brake for instantaneous speed variation. Precision engineered to meet professi | standards for wow, rum- ble and flutter content. Heavy 12” cast aluminum rim-driven turntable. Variable speed control permits adjustment of each speed within + 7% using efficient frictionless magnetic brake. Heavy-duty constant speed 4-pole induction motor freely suspended and isolated by shock-mountings to eliminate vibration transferral. R-C filter network suppresses “‘pop’’ in speaker. Truly a delight for the connoisseur. Size: 13%" x 14” and requires 29/4” clearance above and 3%,” below motorboard. For 110-130V and 60/50 cycle AC. Power consumption 12 watts. Handsome hammertone gray finish. Shpg. wt., 20 Ibs.
Net 49.50
AMDOND APPHIRE
This transcription arm ass *“viscous~ ing is ace
PK-90 VISCOUS-DAMPED TONE ARM
pe of
ball and ket. ‘This to either
pornine ould the tone arm
stylus pressure
and
jumpi 1 one arm accepts all records up to 16” and accommodates virtually all hi-fi cartridges by means of precisely engineered adapters which simplify installation and provide proper
tone arm is a quality companion to the PK-100 with matching finish. Shpg. wt., 24/2 Ibs. SENED cnc Aanactpupiiesisaparketen cakes rabetansaabbesdaorskaane tipres)a++beyyesiiiidains aaah: ian ae asetilaibesises$ Net 19.50
NEW YORK, N. Y
PK. E 100 SIXTH AVE. RAI BOSTON, MASS., 110 Federal St. ‘ AD iO PLAINFIELD, N. J., 139 West 2nd St
NEWARK, N. J., 24 Central Ave
JAMAICA 33: N.Y. 165-08 Liberty Ave, write for FREE Bargain Packed Catalog! BRONX, N. Y., 542 E. Fordham Rd.
RADIO & TELEVISION NEWS
RUsSrcos-enve
@ epnawechee sso
ee @sesgsre>
ri
35 WATT HI-FI AMPLIFIER KIT WITH METERED OUT- PUT AND 4 PUSH-PULL PARALLEL NEW EL84 TUBES
New Lafayette high power amplifier kit with a host of features not in any single amplifier. Calibrated entpus me- ter permits use as aie a recording or reproducing ampl. EL84 power pen- tades provide high peak power and low uired for Petter audio quality. Features exceptional control versatility and ample inputs for all associated custom hi-fi conioment. pc
trol, trols, wo encing witch speaker se! switch, ou balancing adju A ond monitoring jack,
SPECIFICATIONS Y RESPONSE: % 1 db.30-40.000 cps. HUM: 85 d output.
TPUT: 35 watt with 4% total
impedance recorder. TUBE vetoeabk : one feedback loops virtually with auxiliary “Dea ming beauty elity, = the price, 5
EL84, 1-504. OWER: AA 60 cps, Fhe ble escutcheon. Size 12%” L x 9 A combination of high power, and advanced engineering features unmatched at even twice plied in complete kit form with sim- plified easy-to-follow instructi "We 25 Ibs. KT-115—Complete Kit, ....csscccssccccccccccccccccccccvcccccccscsosscoss Net 59.50
7
Se SSB SB SBS BBS SB SSBB eee Be eee eee HIGH FREQUENCY TWEETER
WITH ACOUSTIC LENS DIRECT IMPORTATION MAKES THIS PRICE POSSIBLE!
‘ UNIFORM DISPERS! @ HANDLES 25 WATTS OF POWER © PRICED EXCEPTIONALLY LOW
uency A type apatite directional tendenc
a louvered acoustic lens for uniform sound ip to 25 watts of egg sag” mage ® pewe, =
New high
of hi frequenc notes is overcome = Se he horn and ng acoustic sae which lap matt
ing for exte: mounting w nee ‘desired
dance. Size: 4444" long x 3 >= 4" network, preferably one with a level control, such as the LN-2. tions. Shpg. wt., 5 Ibs.
dispersion
ates
a crossover With full instruc-
Net 14.95
2 WAY SPEAKER SYSTEM 40- 16,000 CYCLES
your Hi-Fi aspira- woofer with
Jecceccescccoccccccccecesccoccccoses NOt 29.00
SY-86—Complete System, same os shame the HW-7 Tweeter with acoustical lens is supplied instead of HK-3. Shoe. wt., 20 Net 36.50 |
LAFAYETTE Mail Order Center
See eee eee testesereeseeeee
January, 1957
. oo on ow oe oe
ELECTRONIC CATALOG PACKED WITH MONEY SAVERS
CHUCK
COPY TO-DAY
LAFAYETTE’'S FM-AM TUNER KIT
* fo tg ory DETAILED INSTRUC-
@ MEETS FCC REQUIREMENTS FOR RADIAT
* = GRID TRIODE AM-
6 ARMSTRONG FM CIRCUIT WITH ISCRIMINATOR @ AFC DEFEAT CIRCUIT WITH FRONT PANEL CONTROL The excellence of its design and the quality of ts rovide this com
Ss as ~y un- low eatures ig FM circuit with miter and Fosser-Gestey
discriminator, Simpli: tuning with Siide-rule dial and flywheel counterweig! defeat circuit combined with tuning control, Attractive etched i ereper aia
SPECIFICATIONS eneavency PARAS: FM, oe 108 MC; AM, 530-1650 KC, ANTENNA meut: J 300 ohms; te Joopath 4 hi —¥ sae “7 antenna. CON AFC Gefeat gootrol : FM, = 5 db
wave SITIVIT J A, Ech NVity: FM, 200 to peak separation; AM, 8 K VEL: 60 db bel
db minimum. ray A seas, Conan 2-6AU6, feats s plu s 1-6X4 acluding knobs). CONBU PTION: 30
= . case
ML-100—Metal cage for above, ‘shoe. Wiig © Wiin cones ccachagasacnaboccusbads [ee 2 8 EOE RB ER ER ER OE OE EE UE UE UF
METAL-CASED CONE TYPE ‘HI-Fl TWEETER
FREQUENCY RESPONSE 2000 -16,000 ae] ade a WATTS OF POWER
cqelen, Mepaniaity ollalant un where pecia Zone type closed so that it can stand c= tts pow A
® CA
CROSSOVER NETWORK «© sun
The frequencies above 2000 epelee are chan- neled to the high freque: tweeter by means of the compris- efficient yy network. The hi; ne
lows are brought acoustic balance means of a coapipwenel variable | level-brilliance
control. Contro le or | res ti: Network matehes. 8- loss reduced to
16. rtion toa minis
tal ° " fee Pert eae at YS
wy Lapis tte 165-08 Liberty Ave. 7 Rad JAMAICA 33: N. Y.
SEND
FREE LAFAYETTE CATALOG
ADDRESS ce me ee
CITY cane eee os ow es www
f
STA’
CUT OUT AND MAIL TODAY!
INVERTERS
for changing your storage battery current to A.C. HOUSEHOLD ELECTRICITY
Auryuhire
in your own car!
ENJOY TV in CAR, Boat or Plane
at | mounted out of sight under dash or in trunk compartment!
ATR INVERTERS
especially designed for operating standard 110 volt A.C. portable TV sets
@ DICTATING MACHINES @ ELECTRIC RAZORS
Iso @ TAPE RECORDERS @ WIRE RECORDERS for @ EXECUTIVES @ OUTDOOR MEN @ SALESMEN @ REPORTERS @ PUBLIC OFFICIALS @ FIELD INSPECTORS @ POLICEMEN @ DOCTORS @ FIREMEN @ LAWYERS, ETC.
See your jobber or write factory
/ NEW MODELS W€ DESIGNS +\/ NEW LITERATURE “4” Battery Eliminators, DC-AC laverters, “ovens
X _
American Tetevision « Rapio Co.
Zuality Products Since 193? SAINT PAUL 1, MINNESOTA, U.S. Ae
Low Plate-Potential Tubes (Continued from page 49)
possible to obtain stability and long life at low voltages with special sur- faces too fragile to long endure under the conditions of high voltage opera- tion. Fig. 6B shows the change in the plate characteristic of the same tube depicted in Fig. 6A after it received special aging.
To gain a partial understanding of these phenomena, reference is made to an article by Matheson and Ner- gaard in the RCA Review, June 1951, entitled “High-Speed Ten-Volt Effect.” This is a study of the behavior of an- ode currents in thermionic diodes with oxide-coated cathodes, operating with plate voltages in the region of 10 volts. In an ideal space-charge limited diode the current is proportional to the 3/2 power of the applied voltage. It was noted, however, that in the neighbor- hood of 10 volts, there was a small deviation from this 3/2 power. This was found only in diodes with an ox- ide-coated cathode. Experiments per- formed to discover the cause in the coating itself gave negative results, so a study was made of the anode.
An experiment was performed where- in an anode which had not previously been exposed to the cathode was ro- tated in place of one that had been in position when the cathode was broken down and activated. This new anode did not exhibit the 10-volt effect until after some time. The effect was then explained by the fact that a layer of barium from the hot cathode had con- densed on the anode, thus giving rise to secondary emission. This phenom- enon is, of course, applicable to triodes and tetrodes—or pentodes. The effect is manifested by the erratic change of R, as the critical plate voltage is ap- proached.
From the foregoing, one might think that this reflection of electrons—if such it is—might be eliminated by pro- viding the anode with an especially clean naked surface. This has not proved feasible because it is hard to long maintain such surfaces in operat- ing vacuum tubes. It has so far not been possible to make good tubes with bright nickel plates. If, however, car- bonized nickel is used and the device is processed in such a way that there is probably a layer of cathode constit-
uents on top of this carbon coating, a composite surface is achieved which seems to be quite effective in curtail- ing reflected electrons.
This situation is analogous to that obtained when an optical lens or prism is coated with a thin film in order to increase light transmission by reducing reflection from the surface. To com- prehend this parallel, you must recall that deBroglie in 1924 advanced the theory that electrons had wave proper- ties as well as the particle characteris- tics assigned to them. This was verified experimentally by Davisson and Ger- mer in 1927. According to this theory, electrons have an associated wave- length which varies inversely as the speed with which they are traveling.
Since 10-volt electrons proceed rather slowly, their wavelength is rather long as such things go. This wavelength is on the order of 3 or 4 angstrom units. This is of the same relative magnitude as the film thick- ness discussed in connection with the plate. With this state of affairs, it is credible that there is a relation be- tween the deBroglie wavelength of the slow-moving electrons and the refrac- tion characteristics of the various me- dia these electrons move through when they impinge on the plate. The writer believes some such machinery operates to curtail reflection which, in turn, makes possible better control of R, at these low operating voltages.
Thus, by using processing techniques not generally suited to vacuum tubes intended for conventional higher-volt- age service, and by altering the elec- trode geometry to take advantage of contact-potential bias, Tung-Sol’s en- gineers have designed a set of tubes that effectively perform with all elec- trodes energized by the 12-volt car battery. With a suitable power trans- istor, this makes possible an automo- bile radio without a vibrator power supply.
These tubes are not final in any sense. The writer believes many more and better types will be developed by the tube industry for this class of service before the day of the all-trans- sistor car radio arrives.
In the development of these tubes, many engineers made worthwhile con- tributions. The program owes a spe- cial debt to Mr. Fred Crawford of the Tung-Sol design department for many important contributions, especially in the field of tube processing.
Y. £ cn* e | 7. + Eoorl2.6 — T Eel 20-4
se 4 - Ecasl2.6
Ec\*
Fig. 6. Effect of
“4
Pa ta -.5
aging on tube char-
—
acteristics, using
type 12AD6 as an ex-
-10
ample. Characteris-
PLATE MA, PLATE MA.
|
aged tube are shown
1-15] in (A), of fully
20
- aged tube in (B).
oO
4 Tt? 16 20 O ¢
PLATE VOLTS
(a)
PLATE VOLTS
12 16 "20 tics of partially
(8)
RADIO & TELEVISION NEWS
‘MICROPHONES & HEADSETS | TELEPHONE & CONTROL EQUIPMENT | . ' RADAR
F-1_ BUTTON CARBON MIC. ‘ @ CONTROL UNIT RM-53— TRANS.
—(Pictured at left) High Gain— Baas oe (Pictured at left.) Used to j
a = used on desk, car, hand, be operate radio equipment and f Transmitter Fre- strapped to chest. Complete 7 # provide remote control and in- L quency 143 to 194
with on-off Mom. 2 s tercom. of such equipment by SC. weine one 3A5
f plas’
. use of the RM-52 Unit a
impe i : Telescoping Anten-
d ; & Phon Blactone, Ae : Be: bs “i ~~
: ei, : wait - # e - i : attery ase for
Coued, Pawel: Tne. op ee , & PL-68 Plugs. EB holding 2/BA-30
used, Checked: $ HS-30 HEADSET — Hearing aid ". _usep: $3.95 new:$5.95 | | | BD > V8 O68 type 1.50 Has on & off Sw
WB onpmrigues . t REMOTE CONTROL RM-52— . ORDER —s || ; Ant. mounts
Sound Powered—One headpiece only U: $1.00 (Pictured at right) Can be used 4 side of batt. case Sound Powered Handset T8-10—Used, checked $5.95 | with RM-53 or used as a separate TODAY! ss 95 TS-9 Handset—Push to talk Sw. No plow. ; telephone system. Up to /% mile. Price:
2 Me ee: < Uses 4 flashlight batt. Also can
TS-13 Handset—Push to talk Sw. vie: oe . i ~ ig kh ts @ Gasact. vente eonteal COMMAND EQUIPMENT
for radio equipment. Provides bias : NEW:
PRACTICE CODE TAPE: | ‘lis & Sisto i nest ae <a cnee SETS: iwxep PAPER TAPES—For Code | Phone Jacks. 550 to 1500 REC., Navy w ant. loop. Sw. 95
practice and training—for Radio Operators, , i Hams, Amateurs, Beginners, and Telegraphers. USED: $2.95 new: $4.95
15 lessons to a Set, on {6mm 400 ft. reels that TS-13 HANDSET for RM-53 or RM-52....Used: $5.95 can be reproduced on TG-34A and TG-10 Keyers.
Price: SET of 19 Reels in wood § @ 18,95 | ce-s rie.o reLerHone—tdeat for private telephone a. 4 system for two or more phones, up to 17 miles. Hand
REELS: Lesson y. Order ber desired, h: $2. ringer, generator with handset, carrying case. Uses 2 by number des +, rs thru 15. Each: $2.00 hlight batt. Price—Used, Checked
WIRE—Weatherproof Twisted Pair: 500 ft. $4.75—135 TAPE PULLER MX-333— vg with | ft. $1.00—2500 ft. $19.95. Per Foot at 1%¢. TRANSFORMERS and CHOKES Ba ce equipment to r of r tape = -130..$. is ith pireton er h the reser der. AG ‘induction motor er Hee eee ene renee aa ETS 115 V. 60 CYCLE PRI. TRANS.: w riction drive for varying spee es on 600 VCT/100 MA—6.3 V/5 A.: 5 V/3 A. .......- $4.95 V. 60 cycle NEW: $12.95; USED: $9.95 SCR-625 Famous ARMY 240 ver/s3 MA—24 = 9A; 6. oi 6 A: 6.3 ; ‘
gt = ow MINE-DETECTOR 700 VET {150 MAxé W/3 A::
—— pe il el For Prospectors, Miners, Oil Companies, Plumb- 2500 V/.015 A.; 2.5 V 175 A.; fe v/ Fer use w/BC-453-454-455- ers, etc. Portable unit for locating all types of . , 7 ° $46 or any sets a 2 buried metal objects up te 24” or more depending Vv. @ 1A, & 250 on size and ground condition. Detection by ae : MA. Ready to ay ‘has * means of a tone. Packed in a chest. Operating 800 /300 : v/s A. 6.95 speaker, volume control, CW weight approx. 15 Ibs. Shipping wt. approx. 40 . 115/230... .$14.95; 24V—1 Amp 1 . plete with cord and plug Ibs. Complete with m 2° 3 t/ree. 5 batteries 5 V/2 A.:5V/2 A.: 5 V2 A; &5V Price....NEW: . Gonse-to0 Vacs v/3
100—156 MC TRANSMITTER Xr 200 MA. i2' ‘rai 12.5 FM RECEIVERS AND & RECEIVER—SCR-522 TRANS. & | 250-0-250 Vac--S0 MA. 24 V. 1 Act and 6.3
-0- RECEIVER: 100—156 MC, 4 Channel, Crystal Control, A.— # H-109—Price TRANSMITTERS AM Voice Operation. 18 Tubes—Trans. : 2/832, 3/12A6, USE faite a/ ds Baccus idl 'Pana: | onte 29 mye, ma mpliete w u , 27 to 38.9 MC. FM RECEIVER Gavamatic, and Genversion tute. tar ame $34 95 Cokes Hy/ 190 BA—200 Cam-—-Spee Frame.. : , x 2” xe, Potted.
Four Pre-selected Channels & Squeich Circuit. Com- teur use—Good Cond. ” —2%"
Pacem atin ua Pome cele or ce OE | Pe tigchanle Ont Tobe a witeat RS | SNS NTO ee 8 Sa Mia ai
i il —-Chas. Only, w/Tu 22.50 without. .. .$9.95 “A” oke—. y -7 ohm, Size: x
‘iso a. "80-528" MECEIVER- ~ Used SCHEMATIC and Conversion Info. Only $2150 | 2%" x 2%" Price: 1.95
Checked 12 V. DYNAMOTOR For BC-923:
ae. Hewes earn ta Ce BC-1158 TRANS. & MODULATOR: TA-12B BENDIX TRANSMITTER KIT of Parts & Wiring Diagram for BC-923....$17.50 Frequency coverage 53.3 to 95 MC. 50 Watt. RF | crsouency 300-600 KC and 3000 to 7000 CW & MCW Deaster, Amster ond Meduiater ee oenee 100 Watt. Four cuparahe.coultiatere easily converted to
4/815 and 10/12SN7 Tubes. Can be to j cover 20-40-80 Meters by using crystal for 10 Meter 27 to 38.9 MC. FM TRANSMITTER . 2 «$39.95 with str peed. — en ote —- _ oe 30 Watt companion to BC-923 Receiver. Four Pre-se- utput Tanks at one time. All controls mounted on lected "Channels, Voltage regulated M O control, usin NEW: Used: . front panel. Uses 3/807, 4/12SK7; also has output /815, 2/68J7, 1 = ww, e* 6AG7, Meter. Size: 154%” x 1044” x oe oom - $32. 95 oltage re- plete with Tubes, Plug and Cable. .
Be. "924 ViSiaerthat.* we ce tad Used: $14.95 NOW—OPERATE BEACON For Conversion—See Surplus Manual poets $2.50 ower & Control Plug #/86-923 or 0-028 $1.00 RECEIVER FROM 12 VOLT MP-28-BA MODULATOR & POWER SUPPLY For
Mountine Base FT-237 f/BC-923 & BC-924.Used: $9.95 | 1° ioogcm BEACON RE- TA-12. Sagulated Bex, Signal Carrier output 75 Watts CEIVE R: 200-400 KC. 5 Class B. Uses 2 1/6 44 a. Dynamotor input
BC-603 RECEIVER: 20-28 MC variable tuning, 10 Pre- | Tubes, 135 KC IF, operates a ag $4°VDE output $40 VDE 450)
Set push button chann wee. e speaker vb c— $9 ae Prices amr: "$14.95—Used: $10.95
10 Tubes: 2/128G7, zyesiz 1/6V6, eis ‘y/sher, é . Prices: : $39.9 : USE : $29. + . Used . 3 ) DYNAMOTOR: 12 -V Sas tel tid a0. mi For 12 Volt operation. use RA-10 BENDIX RECEIVER ic. oy TRANSMITTER: 20- J C, 30 Watt, com- voc ee — 24 VDC. . e 150-1100 KC and 2-10 MC. Excellent for range and genlen to BC-603 Receiver. Crystal control, 10 Pre- Size: 2% * $4, 95 marine use. 7 Tubes: 3/6SK7. 1/6K7, 1/605, 1/6K6G, channels, interphone communication; bes 7” Dyn.. “only 1/6K8. Complete with Dynamotor, MR-9 Cayo Sex. zis & 1/1624 USED: $18. Combination: New BC-1206 & Dynamotor. .. .$12.95 Plugs, Remote Tuning shaft. Size: 10” x 8' 7” DYNAMOTOR: 12 V input: Output 628 VOC 228 MA— <> lieqacte itl eupadh ye tiene tiaee di ae a mc. ated ba ne e Oe ee eee 34.95 Fides bike ti aiaied’ teddies bee ee ae caren, & GENERATORS: RA-10 CA—I2 Volt 150-1100 KC & 2-10 MC. U: $39.95 Transmitter (No Plugs required)....USED: $9.95 vOUTs: volts: a USED ESiw. | RA-10 FA—24 Volt 150-400 KC & 2-10 = : sss 2vDC Corotee Conversion Manual—#i or #2
NATIONAL DIAL or List of contents in each Manual, send oe io TYPE "N" Precision «” ci. $0450 (DA-I2, i METERS:
vided scale with 30 decimal vernier drive 5-1 ratio. Plane- ’ 2 WESTON AC AMMETER:
tary drive fits 4” shaft, 100-0 scale. ae (Pictured) in portable leather case, Prices: 3 for $5.00. { 5 , > . with Test Leads, 242”, 0-15 $5. 95 Each: . 14 3 3.9% AC and 0-3 AC Scale ‘ 2 ‘ ¥ DC AMMETER HOYT: In ‘ : metal case, with | gets. ah” ,
RA-20 POWER SUPPLY 90 6.95 Mirrored Scale 0-15 ADC .
110 V. 60 cycle output 230 VDC 90 MA and 12.6 @ 50 B METER—| 2A. Size: 344” x 5/2” x 6%". 5 60 PE.86 . 0 Yo” Rd. , o 9
Used, Checked 4 4 ; 6.66 RF AMMETER 18-128: 214”
1000 Rd. 12 to 24 VDC PM Dynamotor—Supplies 24 VDC 2 A RF w/Thermocouple 18-895 2"
WRITE US YOUR REQUIREMENTS: from {2 VDC, also 500 V 50 MA. @ 6 VDC will sup- Whatever your needs in Generators, Blowers, Inverters, ply - VDC & 250 V 50 MA, Me'ors, etc.—write us. Chances are we have it!
H ” Sa 3.9 Te? SOUTH MAIN ST. Address Dept. RN @ $5.00 Order Minimum, & 25% LIM A, OHIO Deposit on ©.0.0.’s @ Prices are £.0.8. Lima, Ohio
131
January, 1957
FOP TRADE-INS
ili rafters We trye%o top all offers. Your a it $X 10] trade-ifemakes down payment.
Write ee mer offer.
EkAsy TERMS 90 day$> ‘6pen account or 10% down—u prito) 20 months. We fi- nance. raymnent within 90 days cancels BihGunterest. Write for details. if 1A ALL RECONDITIONED
APPARATUS
A“true" amateur receiv- ts $19.50 Nearly all Rakes and models— er... far superior to ae b san Big savings+-Tea day trial—90- anything npuichee way Cash Price $395.00 day warranty,/90-day full trade manufactured anywhere. back on new pepyatus. Write for bulletin. Wa a |
Vo etelttne 20 Monthly PERSONAL SERVICE—
5.00 49.98 FAST DEWVERY
: x Your inquiries and<drders handled same day. Write, pli@ne or wire us.
COMPLETE STOCKS Henry has everything in the ama- teur equipment field, hew or used
6.00 2.97 . transmitters and-feveivers. Prices Subject to Change 3 “
Write, wire, phone or visit either store today.
“TT re RADIO puatey R RANSMITTER-RECEIVER! on NDS AND RECEIVES THOU- SANDS OF MILES on Amateur 80 and 40 meter bands—also, Aircraft and eid bands (3 RT TERY, Pow.
nat tomy Soot PREPARE FOR A GOOD JOB! SeneittenPower wares up 5 i ae BROADCAST ENGINEER pulls in 2. Pr Send-receive RADIO SERVICING AUTOMATION
y ica STED_PROVEN—SIMPLIFIED_PRAC- i TELEVISION SERVICING |
He Rive 2 ron Te, sioner. (RgvICE) any BLACK & WHITE—COLOR SEND ONLY $5.00 (oitnan “goose “COD. APPROVED FOR VETERANS AND SURVIVORS on Complete "kit includes Yan” parts, tube, “full BUILD — Mh gp ted TIONED
° a © R inet udes ING AIR NDI PLETELY "WIRED, AND. rr Srey" rok 319.03! Steel SEND FOR FREE LITERATURE abinet e ra us waer BALTIMORE TECHNICAL INSTITUTE
WESTERN RADIO
DEPT. BNT-12 KEARNEY, NEBRASKA 1425 EUTAW PLACE, BALTIMORE 17, MD.
132
Spot Radio News (Continued from page 24)
bows use of the motor carrier indus- ry 68 Continuing, the association said that . channel splitting in the 25-50 | band now would relieve the existing and prevent future congestion and pro- | vide the much-needed additional fre- | quencies without substantially affect- | ing equipment investment in this band, | which is bound to grow whether or not | channel splitting is approved. . . .”
The petitioners said that they felt that the surrender of channel 2 to the mobile services would be in line with the removal many years ago of old |channel 1 for reassignment to others. | Also, it was noted, the move would be consistent with the suggestion that all TV go to the high bands.
Telecasters and set makers con- demned the petition, declaring that there is absolutely no need for such a change. Truckers, they said, could use | existing wire facilities at key stopover points, without inconvenience or any disruption of service.
A RESEARCH PROGRAM to study the effects of irregularities in the up- per atmosphere on radio transmission has been undertaken by the Air Re- search and Development Command, in conjunction with the Stanford Re- search Institute at Menlo Park, Cali- fornia. A group at the Institute will gather |information about the reflection of | very-high and ultra-high radio signals; transmission and reception of signals |at these frequencies are frequently | disrupted due to reflection from me- | teor and auroral ionization in the up- | per atmosphere. | The experts at the Institute i. to determine the characteristics o |nal seattering and reflection by me- teor trails in the 100 to 400 megacycle range; similarly the reflection of radio waves by the ionization associated with the aurora borealis will also be studied. The auroras are believed to | be caused by high-speed electrically | charged particles irregularly emitted from the sun which enter the earth’s |upper atmosphere. The earth’s mag- | netic field guides the particles to the polar areas; the aurora borealis is visible in the north polar region and the aurora australis in the Antarctic. Various research and academic or- ganizations have conducted continuing studies of meteoric and auroral ioniza- tion in the frequency range below 100 megacycles. The result has been a much better understanding, at fre- quencies below 50 megacycles, of the frequency-time-amplitude relationship of the echoes. Correlating the lower frequency experiments and theory to the 100-1000 megacycle range, how- ever, has not been scientifically feasi- ble without the anticipated findings of the experiments, such as the Stanford program. :
RADIO & TELEVISION NEWS
WE TRADE HIGHER!
IF YOU DON’T BELIEVE IT, WRITE US TODAY!
BRAND NEW! - FROM HALLICRAFTERS
MODEL SX101 $395.CG0 NET
WRITE FOR FULL DETAILS ABOUT OUR TIME PAYMENT PLAN
All prices f. o. b. St. Louis © Phone. CHestnut 1-1125
/ mm OUR 35TH YEAR alter bie SAM SIR ae lad racinut s RADIO CO. cS
P. O. BOX 4444 + PLAZA STATION
ST. LOUIS 1, MO.
L ~ 0 lial sedi : aR % 3 AMERICA’S LEADING FM TUNER @ IN SENSITIVITY, APPEARANCE AND WORKMANSHIP
Big. @ =
FISHER
FM TUNER
MODEL FM-90
HEN WE INTRODUCED our Model FM-80 FM tuner, it imme-
diately established itself as the leader in the field. Today, the FM-80 is standard equipment in many broadcast stations, where its fabulous sensitivity and absolute reliability make it ideal for pickup of distant FM chain programs, for rebroadcast to the local communities. It took FISHER to improve on FISHER and the result is the new Model FM-90. It is some sixteen years since we produced our first FM tuner. The engineering skill and experience that only time, plenty of it, can bestow, are evident in every aspect of THE FISHER FM-90. We can truly say for it that it is the most advanced FM tuner now available.
Remarkable Features of THE FISHER FM-90
* TWO meters, for micro-accurate tuning. * Revolutionary, dual dynamic limiters, assure noise-free reception where all others fail. = Full wide-band detector for maximum capture ratio. * Exclusive, variable inter-station noise eliminator. * Full limiting on signals as low as 1 microvolt. = Dual triode, cascode-tuned RF stage, four IF stages. * Uniform response, 20 to 20,000 cycles. * Three outputs (Main, Recorder and Multiplex). = Dual antenna inputs (72 ohms or 300 ohms balanced). * Four controls. = 10 tubes plus four matched germanium crystal diodes, * Special circuits for meter operation. = Chassis completely shielded and shock-mounted. * Beautiful, die-cast, brushed brass escutcheon and control panel. * Dipole antenna supplied. ® size: 13 7/16” w.x 6%” high x 8%” deep (plus 1” for knobs). = wor: 15 Ibs.
Professional FM Tuner = $149.50 MAHOGANY OR BLONDE CABINET: $17.95
Prices Slightly Higher in the Far West WRITE TODAY FOR COMPLETE SPECIFICATIONS FISHER RADIO CORP., 21-23 44th DRIVE « L. I. CITY 1° N. Y.
To carry out the project, two large special radars have been designed. One consists of a 50,000-watt FM broadcast transmitter operating at 100. mc., which has been modified for pulse transmission. The second radar utilizes a large klystron, generating power outputs up to 70,000 watts in the 200- to 400-me. range. The transmitters are mounted in large van-type shelters.
Large 60-foot diameter parabolic an- tennas, specially designed by the Insti- tute, will be used with the radars. The antennas will be movable in both ele- vation and azimuth.
A MAN-MADE BRAIN, a computing device which has a memory of 4096 words of 48-bit capacity, is now in op- eration at the Air Force Missile Test center in Cocoa Beach, Florida.
Known as FLAC (Florida Automatic Computer), it has been integrated into the missile-instrumentation system. It serves as the central element in a fa- cility for the reduction of large quan- tities of missile flight test data, pro- ducing answers to problems in a small fraction of the time formerly required.
The device was developed to fill the need for an extremely versatile com- puter; one which would assimilate large amounts of varying types of in- formation at high speed and produce an answer very quickly.
Data recorded during the firing of each missile had to be computed, cor- related and analyzed before the next missile could be launched on its down- range (along the Florida Missile Test Range) flight. Computational devices then in use did not permit completion of this huge job in time to use the in- formation for the following launching.
The new electronic brain is capable of 1750 arithmetical computations per second. In contrast to most computers, it is extremely compact. It consists of a small console, dual tracks packed with 17,000 diodes, circuit elements, 400 tubes used as amplifiers, plus peripheral input-output equipment, and an exceptionally large memory.
An unusual punch-paper tape type of reading device has been developed for the computer.. The tape enables reading of up to 300 characters per second. A potentiality of 600 charac- ters is expected when development work is completed.
A HIGH-SPEED ELECTRONIC missile tester, tagged RACE, which enables highly mobile, guided missile troops to strike targets faster and more effec- tively, was demonstrated recently to Army officers.
The new device was described as the first to bring automation into tactical combat areas to test, troubleshoot and service complex missile systems as they are emplaced at new launching sites.
At the push of a button, the device dynamically tests each missile unit, performing in minutes the hundreds of preflight tests that would consume vital hours by more conventional means. A master console employs
RADIO & TELEVISION NEWS
At all Times in Our Huge Warehouse
Buy one or more of these WORKING TVs to sell or use as your own second set! All Sets in GOOD WORKING condition! Your Choice—Console or Table Model 19” 58.00
When ordering TVs, state whether table model or console is desired. Also preference on make of set. All TVs sent railway press F.O.B, Newark. On any quassticy WIRE or : ALL today!
FREE BONUS AN- TENNA GIVEN WITH ANY TV SET ORDER!!
FREE RCA "CHEATER" CORD
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DON’T PAY MORE FOR SET TESTED LONG LIFE DEPENDABLE RADIO & TV TUBES @ BUY VIDEO INDIVIDUALLY BOXED @ ALL Per GUARANTEED FOR ONE YEAR OR YOUR
Hundred MONEY BACK
Some Standard Brand—Others With Famous VIDEO Brand
6SGT | 12V6GT 6SHT
6SJIGT
80 | 1 7NTGT | 17PTGT | 128Q7 | 11723
GIVEN WITH ANY TUBE ORDER OF $7.00 OR MORE!!
SEND for our FREE
complete TUBE &
PARTS LIST and order blank.
January, 1957
FREE POSTAGE in U.S.A. and Territories on orders over $5.00. 25¢ handling
charge on orders under $5.00. 25% deposit required on
C. O. D.s. Please send approximate postage or freight on Canadian and foreign orders. Subject to prior sale.
IDEO"==
79 CLINTON PL. NEWARK,N. J. ,,
ITS THE BIGGEST AND + ed EVER
PERE 3 ALL NEW 1957
— .
THE GIANT
ie ‘ '
_ BA CATALOG .
BUYING GUIDE FOR EVE
o li
RYTHING IN - -
ELECTRONICS
100'S OF NEW ITEMS LISTED HERE FOR ist TIME
\Y 21 PAGES OF BARGAINS NOT IN ANY
OTHER CATALOG
see RE BURSTEIN-APPLEBEE CO. oS w. 1012-14 McGee St., Kansas City 6, Mo.
0 Send Free B-A Catalog No. 571.
NAME
ADDRESS.
city
STATE
TV—ELECTRONICS WTI GRADUATES IN BIG DEMAND
Take your pick and hold a key top paying job in Television, FM and AM Radio, Broadcasting, Radar, Automation, Compu- ters, Missiles, etc. Over 35 job classifica- tions open to WTI graduates. FCC license coaching included.
Complete, Modern Resident Facilities
You work with the latest laboratory equip-
ment. Non-essential math ang engineering
theory omitted. Approved for veterans.
Free Placement Service. Complete infor-
eet in our FREE Booklet. Write Dept. -257.
WESTERN TELEVISION INSTITUTE
SCHEMATICS— CONVERSIONS FOR SURPLUS GEAR NEW LIST DI MANY ADDITIONS! ae ee DO IT ie seis GOODHEART BEVERLY HILLS, CAL.
GARAGE DOOR OPENER (cc... $24.50
EASY TO INSTALL, SAFE, RELIABLE WRITE for interestina free information .. . TODAY P. E. HAWKINS CO.
631 Prospect Kansas City 24, Mo.
341 W. 18th Street Los Angeles, Calif.
136
lightning-fast computer elements to checkout all units of the entire missile system, provide necessary mainte- nance, and supply critical information for command decision during final countdown.
False answers are avoided by self- testing continuously during the missile checkout and confirming all answers at the master console. If trouble does obtain, the operator is warned imme- diately, naming exact rack, drawer, and chassis location of its own faulty component for immediate replacement.
Go-no-go panel lights monitor rapid progress of the tester through tests through the entire missile system, in- cluding guidance and tracking radars, firing controls, plus missiles on several launchers. At the completion of the checkout, the instrument gives a go signal for the firing station.
An electronic memory supervises the entire checkout procedure by control- ling generators which transmit test signals to each missile unit via cable and microwave radio. The memory knows in advance what responding signals each missile unit should re- turn, confirms each answer and marks wrong ones as troubles.
STATION GRANT ACTIVITY re- mained at its sub-par level, due to al- location difficulties, as this column was being prepared. Accordingly, few authorizations were issued, as the list- ing on page 22 reveals.
AN ERECTOR SET technique is speed- ing up the flight testing of airborne electronic equipment at the Wright Air Development Center in Dayton, Ohio.
The new approach has reduced to a matter of days the time required to install experimental electronic gear in a C-131B test plane. Previously re- quired were weeks and even months in the case of especially complex installa- tions.
In the new plan, electronic equip- ment is mounted on 30 by 30 inch racks in the shop. This can be done while the test plane is flight testing other items of equipment. When it lands, racks of equipment already test- ed are removed. The new racks are then bolted to plates anchored in the floor and ceiling of the plane, the elec- trical system is plugged in, and the plane takes to the air for another test.
A NUMBER OF EXPERTS have fore- cast that industry is setting an un- paralleled growth pace, but a few weeks ago, the immensity of this ex- pansion was graphically translated into some significant figures. It was noted that sales and revenues of the elec- tronics industry, currently an $11%- billion item, would within the next decade exceed $22-billion annually.
In an appraisal of the present and future of the entire field, it was dis- closed that the present investment of more than $9-billion will grow to near- ly $1544-billion by 1966.
Fantastic growth figures for so young an industry! . ... L. W.
RADIO & TELEVISION NEWS
Descri
R-1/ARR-1 Receiver... .$2.95
Described in Radio TV News, Jan. 1949 for use as 220 Me. converter. Essentially a two stage RF acorn tube superhet converter as it now stands. Also can be used for a preselector.. Small enough for mobile; only 312” wx 3” hx 10" d. Rugged aluminum con- struction. Has four 954 acorn tubes. Filaments now operate on 12 or 24 V. by merely throwing switch in unit or can be easily modified for 6 v. operation. Dial is calibrated in range of 234-258 Mc. Operation can be changed for use from 50 to possibly 300 Me. Cover not shown but included. Complete with _conver- sion as written in above mag. Brand new.
Ste webs BE Pais in's: 0 wipsl Bie 0.0 6-0 6 wee Vee
ARR-1 Antenna for above
freqs. Ship. wt. 1
Co-axial antenna relay for use with above or ort transmitter-receiver combinations. Ship. $i 2 wt. 2 Ibs. New..... Tero. s
ER-25-6, 6 V. 25 AH Storage Battery
Plastic case size 7¥/2” x 2%," x 6%" h. Shipped dry charged. Fill with 1.265 sp. g. sulphuric acid. Ship. wt. 8 Ibs.
NeW. cosccvcesccess -SBO8
RL-42-B Antenna Reel/Motor....$2.50
Used originally for remote
controlling of automatic
trailing wire antenna.
Motor is Ys hp. x 24 V.
DC with oil-less sleeve bearings.
The gear train, breaking and
disconnect mechanism, reversi-
ble and variable speed motor makes this an ideal unit
for conversion to coil winders, etc. Ship. wt. approx. 5 lbs. $2.50.
Leeds & Northrup Micromax Recorders
Strip type recorder used for controlling and recording wide variety of processes. Used om for temp. range of 350-550° C. but may be anged for other applications. Operates on Wheatstone bridge principle using AC galvanometer movement. Original cost sev- eral times our low price. Removed from demilitarized equipment which in many cases was new. Sold as used but guaranteed, or money back if not satisfied. Ship. wt. approx. 165 lbs., $179.50 Ea.
BAILEY METER RECORDERS
Used in application as above at same tem- perature range, etc. Operates on electronic principles using vacu- um tubes. Used but guaranteed. Ship. wt. 165 lbs. $65.00 Ea,
Complete with all 14 tubes, dynamotor and wobbula- tor. Frequency 460 mc. Excellent condi- tion. Ship. wt. 23 Ibs. Sale Price....... s
Freq. Crystals ... Less Than
5e Ea. Imagine crystals costing Govnmt. $3.50 to $12.50 ea. in this assort- ment. 100 brand new; various freqs.; plenty in ham bands. Practically all types of holders; = mounted; guaranteed > oscillate. Assortmeat of 10 ie ir 6 Mitel sk. palinweai. 4 e
ESSE RADIO C
January, 1957
WEST SOUTH ST e INDIANAPOLIS 25, IND
42
OAV-1 TEST SIG- NAL GENERATOR $19.95
This signal generator
was used to provide a
test signal of constant
frequency ior operation
and alignment of IF am-
plifier stages in the CG-
46 ACQ type receivers.
The generator covers the range between 150-250 megacycles. Amplitude modulated square wave out- put is obtained at frequencies of .1, 1, 10 and 100 ke, depending on the position of the freq. mod, pulse switch. A 15 Mc signal is also provided by a second ose stage. Power is supplied by internal 115 V 60 cycle AC supply connected to source by cord provided. Brand new with instruction book.
eS a epee ree bd
Brand New
12 V. Dynamotor DM-40 Input: 12-14,V. 3.4 A. Output: 172 V.—1388 MA. An ideal dynamotor to adapt to mobile uses on the new 12 V. cars. Don’t pass up this buy even if your in- tended uses are not imme- diate. Size 634” L. x 34/2” dia. 4” lead with 6 pin Jones plug. Ship. wt. 74/2 Ibs.... i» é ‘
14 Amp. Battery Charger While Supply Lasts
Cost Govmt. $300 ea. Our purchase of large quantity allows this bar- gain. Charges 6, 12, or 3 teries at 14 amp. rate erates from 110 V. DC, Ward-Leonard. Size 12” hx 10° d. Brand new in orig. pack- ing; wt. approx. 80 lbs. They'll go fast at this low price, so order now ....- ose ee $7.80
M-1 ODOGRAPH.............-+ $179.50
An instrument used for vehicular map- ping of terrain over which it is driven. Compass
tion is
thru a photo
trie circuit to plotting unit which combines this formation with
hours ry normally requir es instruments
T m that parts can be
lapted ~ other uses such as the 1 unit to auto
a
pilot boat control, etc. Ship. wt. 200 Ibs. U.S. Corps of Engineers rebuilt units. .$179.S0 complete Brand new units $279.50 complete
Golf Car Motor $4.50
New 13% hr. battery-oper- ated motor for: building up your golf car or other use. from 12 to 24V.
to 6900 RPM.
18 Ibs... ee ceee Trip Relay
Protect automatic machines in case of clogging or choking. Instantaneous class 9055 Type N. Mfg. by Square D Co. 600 V. max. Three ranges available—-.067—.15 amp.; 23-47 56-117 amp. State choice. 4 Ibs.
amp.; and Ship. wt. Brand new
PERMOFLUX HI-FI SPEAKERS
Hi-fi series Permofiux 61-1 speakers. Six inch, frequency response 50-12,000 cps. Originally $10.00 ea. Ship. wt. 3 Ibs.
Sale Price cee eo OM,
TU-10-B Tuning Units—$1.95 ea.
Special!
Used in the BC-375 transmitter, but the most pecewebie and acceptable piece rplus gear for obtaining good cheap useable parts. -B contains three ‘doub spaced transmitting type ( and 7 plate varieties, 3 ents transmitting type micas, ‘3 isolantite shaft couplings, antenna coupling switch, two precision vernier dials, chokes, inductances and other use- Better order plenty before supply is exhausted in stock. sa
cE, Used, ea ARR-1 Test Oselliator for 234-258 me sing sold 1 porns
operated (not inel.). ze
Dry battery Excellent to new condition.
with tubes. Ship.
REMIT SHIPPING CHARGE AND ® DERS. OTHERWISE ORDER WILL BE SHIPPED EXPRESS COLLECT. ALL ITEMS GUARANTEED TO YOUR SATISFACTION OR MONEY ® REFUNDED IF RETURNED PREPAID WITHIN 10 DAYS OF RECEIPT
TEST SET EE-1 NEW—$i?.50
A test set for aircraft containing AC & DC volt, ohms, meter, tachometer, pressure gauge and test gauge cord and tools. In aluminum suitcase type case that opens forming sloping 2 sec. panel. Ideal for your test bench applications. Cost hundreds of dollars but yours in original —* shipping container. Ship. wt. 270 lbs. $19.5
Kerosene or GASOLENE HEATERS
Special! Brand New Evans, flame 50,000 BTU heater. Originally used for arctic aircraft heaters in far north. Ideal for camping, field-day or in place of salamander. Terrific out- door camp stove. Compact 10” dia. x 12” high. Lightweight. Cost gov- ernment many times low price Shipped in original packing. Ship wt, 47 Ibs. Reduced Sale Price $4.95
blue-
New Torque Amplifier Only $9.75 FOR USE WITH SYNCHROS SIZE 5, 6, 7 Provides torque amplifica- tion and ease in rotation of input shaft. Rotating power applied to input shaft is reproduced in any direction on the output shaft. Torque ae. entirely by a 1/40 HP 11 . AC motor through gear 805 planetary drive hookup. Speed varies direct- ly with rotation of shaft with noticeable of accuracy. Motor requires capacitor of 85-120 mfd. for starting. Designed for use on gun control devices and cost the Gvnmt. hundreds of dollars to mfg. In cast aluminum case. Size: 12” h. x 5694” w. x 742” d. Wet. 23 Ibs. Packed in er wood box. Brand New .
Starting capacitor aa nt tense “Amplifier.
45 Ibs. . $9.95
~~ wt.
- $1.00
RADIATION COUNTER $17.9
Manufactured by Barker-Wil- liamson for AEC. Contains 0-20 microamp meter and all tubes, Battery operated (not included).
Ship. wt. 17 y | 95 s
Brand New - Oil Capacitors
4 mfd 600 mfd. we Vv. GE
m -12 mfd. 1 5000 v ‘Gk All leading popular brands. sl.oopworn, Guaranteed
SYNCHRO
Motor and Generator Only $9.95 Per Pair
By simply connecting like wires each unit and applying 110 V. 60 cycle current to junction of two rotor wires you have an elec- trical equivalent of a flexible shaft without the usual friction, backlash, and error. Dream up your own applications suc as remote reading weather remote control antenna rotation. lieuid level indicators, ete. Pon- 1.x31%” dia.). times our low r w Ths, % pair. Removed from ‘equip Guaranteed. Per pair.
G-E SELSYN 2J1G1—$4.95 PR.
Brand new small size Sel- for beam direction ator and other de- 5 volt 400 cy- Caaiagrt rotors in series on 115 V. Will operate for intermittent duty on 60 cycles, approx, ? size 21/4” dia. x 41%/2” long. Shpg. wt. 8 Ibs. per pair. a cs aa ee ee
Terr. “All new;
$9.95
-pr. $4.95
INSTRUCTIONS WITH ALL OR-
137
“att AN ALL NEW 4).
ELECTROSTATIC TWEETER
(MODEL —
REMARKABLE VALUE AT ONLY $99,°°
Combine this all New Electro- static Tweeter with your present speaker system and realize the full capabilities of your Hi Fidelity System.
FEATURES
Plug in combination with your present speaker system
Built in crossover network and matching transformer Smooth response from 5000 to beyond 20,000 cycles Excellent transient response Uniform distribution of sound 360 horizontal omni-direc- tional sound.
Dimensions: 442" x 442" x 12” Hand rubbed cabinet in ma- hogany or blonde
Radiating assembly gvaran- teed for 2 yrs.
Manufactured in the U.S.A. Available at all leading Hi-Fi dealers. If your dealer can not supply, write
ELECTRONICS CORP. pose pRamaroRe AVE PHA. 26, PA
DEALER'S INQUIRIES
INVITED. WRITE DEPT. R.
138
CS
NEW B&O MICROPHONE
Fenton Company, 15 Moore St., New
York 4, N. Y., has pert introduced
mii
ponaane
a new version of its popular B&O 50 microphone.
The new unit, the B&O 53, uses an identical magnet and ribbon assembly but has a multi-tapped output trans- former having output impedances of 50, 250, and 40,000 ohms. It is housed in a cast iron body for better shield- ing. It weighs 19 ounces.
Supplied in either matte finish “TV grey” or satin finish chrome, the B&O 53 is supplied with 20 feet of cable, a female microphone connector, and snap-on bayonet adapter for % x 27” stand.
A new “Binor” rig for the correct positioning of microphones for stereo- phonic recordings is also being offered by the firm. The rig is designed to work with two of the B&O 50’s or B&O 53’s. Write the company for full de- tails on the mikes and the rig.
MASCO “MUSIC MASTER"
Mark Simpson Manufacturing Co., Inc., 32-28 49th St., Long Island City 3, N. Y., has introduced its Model AFR “Music Master,” a decorator-styled single chassis FM-AM tuner and 10- watt amplifier.
The unit also incorporates a quality preamp which permits the use of any good grade phono pickup. The preamp
ee
is fully equalized ‘for all LP seuats and has separate bass and treble con- trols.
At 10 watts audio output, the fre- quency range is from 20 to 20,000 cps with less than 1% distortion. The unit is housed in a black enclosure with a gold front panel and an illuminated tuning scale.
NEW G-E TWEETER
General Electric Company, Electron- ics Park, Syracuse, N. Y., has released a new high-frequency speaker which is rated at 8 watts.
The Model A1-404 is 2%” in diame- ter with a 1-inch aluminum voice coil. It uses a 6.8 ounce Alnico V magnet. The speaker is shielded for protection against accidental impact damage.
The tweeter will operate with any 8-ohm single-cone speaker, irrespective of size. It has a frequency response, substantially flat, from 1500 to 15,000 cps. One of its most important fea- tures is the wide angle of dispersion at higher frequencies, resulting in smoother and more natural sound re- production. The angle of dispersion is between 90 and 180 degrees. The di- rect radiator design eliminates the possibility of acoustic reflections char- acterizing horn-type operation.
NEW AMPEX STEREO CONSOLE Ampex Corporation, 934 Charter St., Redwood City, Cal., has added a con-
nA,
sole music system to its line of monau- ral and stereo tape equipment.
The new unit is a combination tape recorder and stereo phonograph with two separate amplifier-speaker sys- tems arranged for the realistic projec- tion of both stereo and monaural sound. The switching and control cir- cuits are designed so that program ma- terial from the AM-FM radio or three- speed record changer may be listened to and recorded simultaneously. A jack is provided so that TV sound may also be played and recorded through the system.
RADIO & TELEVISION NEWS
Another new circuit makes it possi- ble to mix and record with the pro- gram sound which is picked up by the professional microphone included with the system. An illuminated program
level meter and an accurate tape po- |
sition indicator further simplify the recording of professional calibre tapes. Stereophonically recorded tapes are played separately from the two re-
corded sound tracks through the dual
amplifier-speaker systems.
Full details on the Model A423 con- |
sole and other units in the company’s new “A” line are available on request.
JENSEN-CABINART KITS Jensen Manufacturing Company of Chicago and G &¢ H Wood Products
= ae tee bse! Dye.
Co., Inc. of Brooklyn, N. Y., have en- tered into an agreement whereby “Cabinart” will manufacture and sell a line of Jensen-designed cabinet kits especially for use with that firm’s loudspeakers.
Seven basic cabinet kits are now be- ing offered, ranging from the “Duette” to the “Imperial.” A-choice of highboy corner, which may be used against a sidewall, or lowboy, non-corner styles, is available for systems using 12” and 15” woofers.
All needed parts are furnished with the cabinet kit series, including hard- ware. The only tools needed to assem- ble the kits are a screwdriver, pliers, and a stapler.
OSCILLATOR WAND The Stancil-Hoffman Corporation, 921 N. Highland Ave., Hollywood 38,
ill
Cal., is now offering a new mainte- nance tool for fixed and portable mag- netic recording equipment.
The Model AO11 oscillator wand is a source of either a 1000 cps or an 8000 cps tone. When it is held close to
January, 1957
FAIRCHILD
DESIGN
We’re often asked—“‘How will the use of the Fair- child Arm in conjunction with the Fairchild Cart- ridge increase the performance of my high fidelity system?” Since the 280A Arm is the housing best designed for this famed cartridge, the results will be immediately apparent to the critical listener.
It will reduce the fundamental resonance which is determined by the mass of the arm and the com- pliance of the cartridge.
It will result in excellent tracking of the most heavily recorded passages.
It will minimize side thrust and hence reduce distortion.
It will allow complete freedom of motion without vibration or erratic performance.
It will reduce tracking error to a minimum.
It will provide unusual features of convenience and ease in handling.
Most important, it will assure superb sound.
There is no question that a speaker housing is almost as important
as the speaker itself. Similarly,
the housing for the cartridge is
equally important but often overlooked. The Model 280A Arm, the result of much experimentation and fundamental research* can properly be classified as professional in performance, yet
is modestly priced at only $33.95.
*Journal of the Audio Engineering Society, Volume 2, Number 3, July, 1954.
Find out what to look for in a transcription arm. Write Department ‘'S" for free illustrated booklet “HOW GOOD IS YOUR ARM."
FAIRCHILD
RECORDING EQUIPMENT COMPANY 10-40 45th Avenue, Long isiand City 1, New York
Introducing
DEE
DUOTONE FIDELITY FOCUS Loudspeakers
INew Engineering Technique Assures You— Bell-Clear Highs; Vibrant-Undistorted Lows.
DUOTONE — For a quarter of a century, leader in the high fidelity industry, pre- sents for the first time, DFF, DUOTONE FIDELITY FOCUS LOUDSPEAKERS. A new high in manufacturing standards and pro- cedures assures you of a superb quality seldom found in most other loudspeakers. Rigid specifications adhered to and exacting field trials were made before this fine line was presented to the public. It was only the results of these exhaustive tests that lassured us of a product worthy of the HI-Fi enthusiasts interests. Whether you choose a coaxial speaker such as the Royal or Medal- ion, or a woofer-tweeter combination like the Supreme and the Duchess, you will be more than satisfied with the excellent re- sponse these speakers afford. Stop into your HI-FI dealer's showroom and ask to hear them. Your reward will be the self- satisfaction of hearing excellent high fidel- ity sound reproduction. There's a DUOTONE FIDELITY FOCUS LOUDSPEAKER to match your system and they ore priced to $53.97.
Write today for our FREE new booklet, “An Objective Study of Loudspeakers”. It's de- signed to help you choose and install your speaker system.
Sa Ze Sa
WIDUNE
- - = a
the playback head, either a 1000 or 8000 cycle tone will be induced into the playback head to check operation of the playback amplifier or film pho- nograph.
Held close to a dynamic microphone or any other moving coil pickup, the wand will induce the same tones. The wand may also be ‘nserted in the input of a microphone preamplifier in order to record 1000 or 8000 cycles. The wand weighs only 9 ounces and is 8 inches long and 1% inches in diameter.
CLOCK SPEAKER
American Elite, Inc., 7 Park Ave., New York 16, N. Y., has recently in- troduced a novel “clock speaker,” the Model WLU-30.
The speaker is a 7” unit with 4 watt input and impedance of 5 ohms. Over- all dimensions of clock speaker are 12%4” diameter and 4” high. It is avail- able in ebony or ivory finishes.
TAPE TRANSPORTS Telectro Industries Corp., 35-18 37th St., Long Island City 1, N. Y., is now
offering a new series of tape transport mechanisms suitable for hi-fi applica- tions, studio work, and for telemeter- ing and data recorder usage.
Tape speeds are 15, 30, and 60 inches per second. Instantaneous change of speed with automatic compensation is available at all three speeds. Push- button controls are provided for start, stop, wind, rewind, and record.
These new tape transport mechan- isms are available in any number and combination of channels up to 28. Write the company for full details on specific applications.
SPEAKER SELECTOR
Dynamic Electronics-New York, Inc., 73-79 Woodhaven Blvd., Forest Hills, N. Y., is now offering its ‘“Hi-3” speaker selector to the audiophile and audio trade.
The Model No. DS77 is designed to be used for temporary or permanent speaker coupling and comparison checks, and in connection with an audio output for switching to as many as three speakers at remote points.
The unit comes in a compact all- metal case with a 3-position switch. Write the manufacturer for full de- tails and prices.
“SOUNDBOOKS" Audio Master Corp.,.17 East 45th St., New York 17, N. Y., is now mar-
keting a new and improved “Tefifon” unit which provides up to eight hours of musical selections.
“Tefifon” utilizes cartridges in the form of compact plastic-covered “Soundbooks,” weighing less than a
pound each. These are comprised of unbreakable vinylite soundreels which need no winding or rewinding. The “Soundbook” is placed on the center spindle of the player, the control knob is switched on, the pickup placed against the reel, and 8-hours of un- interrupted music results. Additional cartridges are being released monthly.
Write the U. S. distributor for full details on the unit and on the program material available.
BASS—TREBLE EQUALIZER
Vidaire Electronics Mfg. Corp., Lyn- brook, N. Y., has added a bass and treble equalizer to its line of radio, TV, and audio accessories.
The Model EQ-6 is of the network type and is designed for use in hi-fi speaker systems to compensate for speaker system deficiencies such as poor response of the speaker or en- closure and acoustical properties of the room.
Individual control of bass and treble is provided over a range of —6 db to
ae me
+3 db for bass and —3 db and +3 db for treble. The equalizer will operate with either 8- or 16-ohm speaker sys- tems.
SCOTT AM-FM TUNER
Hermon Hosmer Scott, Inc., 385 Put- nam Ave., Cambridge 39, Mass., is now offering its new Type 331-B AM-FM tuner with provision for stereo.
Carrying all of the features of the firm’s 330-B tuner, the new unit also includes a complete equalizer-preamp so that the only addition required is a power amplifier to make a complete installation that includes a flexible
RADIO & TELEVISION NEWS
Circle troduc venier The opposi band holdin the r offers
eye al space two ol The on se\ liverec cost.
The neaut, cartric interes
The contail of all cartric illustré
“front end” and versatile stereo AM- FM tuner.
The selector switch includes posi- tions fur five equalization curves and two high-level inputs; RIAA-NARTB- Ortho, original AES, original Colwm- bia, original London, Eur. 78, and
other positions. FM, AM wide range, AM normal, AM distance, tape, TV, are also included. Bass and treble con- trols are provided, offering maximum boost of 17 db at 30 cps, and 19 db at 20,000 cps.
There are two low-level magnetic phono inputs and two high-level.inputs for tape and TV. Outputs are for main output, tape recorder output, AM and FM binaural outputs, and provision for connecting a dynamic noise suppressor.
The case measures 15%” x 4%” x 12%” and the unit weighs 17 pounds.
“NO-SPILL REEL"
ORRadio Industries, Inc., Shamrock Circle, Opelika, Ala., has recently in- troduced a “No-Spill Reel” as a con- ead for oe vr ae tch Here’s a specia/ high fidelity catalog that you'll eepeaha sate of a oe - genctese find particularly useful, because we have included on/y equipment which band is slipped over the two notches, we at MusiCraft consider the 4est—from the standpoint of compatibility holding the tape securely in place on and stable operating efficiency—in every price range. the reel. In addition, the new reel Page after page pictures the newest high fidelity equipment with offers easier access to the threading detailed information about characteristics and specifications.
Whatever you want—whatever you need—speakers, tuners, ampli-
fiers, turntables, “do-it-yourself” kits, etc—MusiCraft’s new catalog features all the top quality components from leading manufacturers.
48 East Oak Street address Chicago 11, Illinois
Delaware 7-4150
motor t ecco
eye and 28 square inches of inlieiate
space on the four large flange areas, two on each side. The company’s “Irish” brand tapes on seven-inch reels are all being de- livered on the new reels at no extra There Is Only One Original Dependable NO.- NOISE cost. Cleans, lubricates, protects Volume . . not a carbon-tet solution. TUNER-TONIC
CATALOGUES Still available in the new 6 with PERMA-FILM Control Os. spray Can. Cleans, lubricates, restores PICKUP CARTRIDGE DATA and type. Won’t change or af-
Net to servicemen—$2.25 all tuners including wafer : : fect capacities, inductance The Astatic Corporation of Con- Contact fnaniatann Ge peoons neaut, Ohio, has released a new pickup — ties. For television,” ra- cartridge catalogue which should be of whe ali, move, “oxidation and Me SS Pe “ r nuefin interest to audiophiles. Perma jon toxic,
The single sheet catalogue, No. 33-1, Film
contains a complete, up-to-date listing idea: oa, ‘botties and San per form-
of all of the company’s phono pickup tie. ety 00 ANE RARE, Eh ET ery tributor. cause a small amount
cartridges, new and old stock numbers, } does the job!
illustrations of each cartridge, prices, ELECTRONIC CHEMICAL CORP ; » : ;
and pertinent specifications. Also available is a new 8-page pick- $13 Commusipew Avenue dereoy Gity 4M. J.
January, 1957
up cartridge cross reference index and needle listing, No. CRC-56. This index
DO You WANT A BETTER AMPLIFIER 9 provides a handy reference for distrib-
bad utors and countermen of all Astatic
cartridges as well as the cartridges of ater 4 USE A DYNACO other makes that may be replaced by :
Build q 50 watt DYNAKIT Astatic models. Also included in this playing
markn | TRANSFORMER TO index is a complete listing of all of the ee,
MODERNIZE YOUR company’s needles and its line of cut- time, i
ting heads. PRESENT AMPLIFIER aeration presen
D fideli SHURE REPLACEMENT MANUAL true tk ynaco super-fidelity transformers are signed a new design which permits lower dis- Shure Brothers, Inc., 222 Hartrey, groove
tortion and wider frequency response | Evanston, Ill, is now offering copies the fol in high fidelity amplifiers. Models are of its new pocket-size replacement
available from 10 to 100 watts includ- manual, the RM-56. ered: ing the 50 watt A-430 transformer Designed for countermen and tech- A ce which cam be qend to increase the nicians, the manual gives complete re- rages races phages <a cegmandenl placement information and technical in the
$ 75 eit data on ceramic and crystal pickup eine MODELS cartridges and magnetic recording of a
A-410 10 watts 6V6, EL-84. $14.95 heads. derapin A-420 25 watts KT-66 The manual is available without ‘ P A premium kit for the audio perfectionist, the Dynakit 5881, 3 4 charge from all of the company’s dis- omina sounds better because it is designed for outstanding A-430 50 6550, EL . be incr transient response and stability, for higher power at low + ‘ecay) ’ ” 29.95 tributors or from the sales department distortion, and for complete and accurate reproduci- 3 r, . of the manufacturer as the bility. The improvement over conventional circuits is A-440 100 watts 6550 ’ 50} quate t immediately apparent to the discriminating listener. A-450 100 watts PP par tortion The Dynakit combines unequalled quality with econ- 6550, EL-34 ER Po re If th omy and simplicity. It features the finest of parts, like Col eihh dented ‘primerics except the superb Dynaco A-430 output transformer. At the wie hi hie - ‘ at a aoe mv that th same time construction is greatly simplified by the Dy- | **"" hode f ibe “k) ne ae ae the ave naco pre-assembled printed circuit unit which includes or cathode feedbac th ty the major portion of the wiring. Full data and details of Williamson ra e sty: The Dynakit is sold complete with all parts and the pre- Amplifier conversion available on re- C A L uss N 2 R record | 19 | revoluti
wired printed circuit assembly. Complete specifications quest.
are available on request. with ar AVAILABLE FROM ELECTRONIC PARTS AND AUDIO DISTRIBUTORS of E V BE N TS 4Ea ject to
using v
DYNA COMPANY, ep. rt, 5142 Master St., Philadelphia 31, Pa. Stee, Aled on cits a ee It th which | if , JANUARY 14-15 some ol oure Symposium on Reliability and Quality tion, e
y HERE’S HOW TO Control in Electronics. Sponsored by a viscoi
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interested ; GET YOUR START D. C. Contact C. M. Reyerson, RCA conditic No matter what si JANUARY 23-25 then a ' you need! A o> Colorado. Dr. J. R. Wait of NBS, Boul- handling . training that can help JANUARY 28-29 loud one else i] . good loudspeaker . . . Speakers career! and Applications. Engineering Societies for. 32 fascinating pages, | oldest book of its kind son, 1539 Deer Park, Mountainside, one else grams and delightful car- clear and complete. More gram information. dental « from this giant book than everyone who plans to purchase one! any other of its type— Basic Electricity (over 300 beginners 35 Bogart Ave., Port Washington, Long always \ Covers principles, theories and practices that are ; basic to even the most modern equipment. 972 FEBRUARY 6-9 nr Me pages; 508 pictures. 856 helpful self-review test Fidel Sh S d by th year ma ee es ee ed Price only $6.50. High Fidelity Show. Sponsored by the next ye 80 South Kensico Ave., White Plains, N. Y. Dept. RN-17, RINEHART & CO., INC., Cahn, Executive Secretary, Institute of fidelity s
RETMA. Statler Hotel, Washington, tage; if in true Bldg. 10-6, Camden 2, N. J., for full de- warping hich fideli IN RADIO RLECTRONICS tails on program. see tha
igh fideli part of radio-TV- Very-low-frequency Symposium. Sponsored the adv: electronics you plan a DI by the Denver- Boulder chapter of the up agal to enter, this is <it IRE and Boulder Laboratories of the You | the BASIC training Dp} . NBS. Boulder Laboratories, Boulder, best pre +++ Lhe authoritative, easy- i Here’s basic training ‘ ; f _ to-understand story of how Speaking j you can really understand der, in charge oF program whether a hi-fi loudspeaker works. im DS ti wee for 4 gust oun equipme Tells you how to judge a radio-television-electronic Symposium on Microwave Ferrite Devices ti b imes what to look for, listen oy IM ee. Auditorium, New York. Tore M. Ander- If the ec including dozens of dia- ! . . and still a best seller : “ei x 4 S - ; because it is so amazingly N. J., in charge of publ city and pro a: toons. Only book like it! A wonderful guide experts now in electronics | S for everyone who has a hi-fi system. A must for | got their basic training Feats JANUARY 30 Pes 7 I . Chirarai Electronics in Aviation Day. Held at see . Yours FREE—just send a dime to cover cost | and they'll recommend it Complete basic Sheraton Astor Hotel, New York City. especia of mailing. to you today! Starts with training for Information on program from D. S. Little, have to University Loudspeakers, Inc., White Plains, N. ¥. | pages) then takes you step by. step through the entire radio-electronics field. Island, N. Y. more cc questions. High Fidelity M fact re Ee Te nstitute of High Fidelity Manutacturers. STUDY 10 DAYS FREE! \ Location to be announced. Contact S. tone arn 232 Madison Ave., New York 16, N. Y. . seth : , Send Ghirardi’s RADIO PHYSICS COURSE High Fidelity Manufacturers, P. O. Box for impr
Gentiemen: Please send me my copy of “Speaking about Loudspeakers.” Enclosed is Dime to cover the cost of mailing.
home-training book for 10 days free examination. 284, Mineola, New York. manufac I will then either return book promptly or Cry don’t we
you $6.50 plus postage in full payment. (SAVE FEBRUARY 7-8 - is produ
Send $6.50 with order and we pay postage. Same 10-day return privilege with money refunded.) W est Coast Convention of Audio Engi- fect peas
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Angeles. Contact Ross A. Snyder, Am- pex Corp., Redwood City, California, tem—yo time and
fidelity e
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Citv. Zone, State l the western vice-president of the AES, OUTSIDE U.8.A.—$7.00 cash only "Money back P if book is returned in 10 days.
ere an apinens sans siete dailp alphas arian com ene eoan eonel January,
CITY. STATE
for further information.
CO ee Te ee 142 RADIO & TELEVISION NEWS
(Continued from page 53) playing perfectly flat discs viscous damping is no disadvantage and is a useful safety precaution, but if, at any time, it is required to play discs that are even slightly warped, the viscous damping can be a disadvantage. It is true that the damping is usually de- signed so the stylus will not leave the groove under these circumstances, but the following fact should be consid- ered:
A certain minimum stylus force is necessary to maintain correct tracking in the groove. Viscous damping will cause a greater variation from the average stylus force than will an arm of the same inertia without viscous damping. This means that either the nominal or average stylus force must be increased so the minimum force, as the arm is falling, is always ade- quate to maintain tracking or else dis- tortion will occur during this period.
If the stylus force is increased so that the minimum is always adequate, the average and maximum forces on the stylus will be such as to increase record wear on those parts of the revolution. This means that a record with any trace of warp will be sub- ject to uneven wear from an arm using viscous damping.
It thus appears to be a question of which you value most: if you have some old discs that are in good condi- tion, except for being warped, then a viscous damped arm is a disadvan- tage; if all of the discs are in good condition and do not suffer from warping, and you take precautions to see that they do not develop warps then a viscous damped arm does have the advantage of protecting your pick- up against accidental dropping.
You may of course feel that the best precaution against this is careful handling. This in turn depends on whether you intend only to handle the equipment yourself, or whether some- one else in the household may some- times be permitted to play records. If the equipment is available for some- one else to use, then viscous damping is a useful protection against acci- dental damage.
Yes, audio is a perfectionist’s hobby. Manufacturers of audio equipment, especially tone arms and pickups, also have to be perfectionists, so they are always working to produce better and more competitive products. So what may be the best choice of arm this year may not still be the best choice next year. Just at the moment the tone arm is one component in a high- fidelity system in which there is room for improvement and on which various manufacturers are working. However, don’t wait until the perfect tone arm is produced: if you wait for the per- fect tone arm—or indeed for perfection in any other portion of an audio sys- tem—you will have to wait a very long time and you will never get any high- fidelity equipment at all! —30—
January, 1957
BEST BUY IN HI-FI
eroeeten os
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10PG 10 Watt High Fidelity Amplifier
Here is new styling with a full set of controls providing exceptional flexibility in a moderately priced amplifier. A simple efficient flat compact design features modern feedback circuitry, rec- ord compensator, loudness control, wide range bass and treble controls, rumble and scratch filters, and six inputs, in- cluding one for tape head. Frequency Response: +0.5 DB. 20 to 20,000 CPS. Distortion: 2% harmonic and 3% intermodulation at 10 watts.
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The best buy in the medium priced field. The all new deluxe 15PG fea- tures the most advanced circuitry, the highest quality components and greater flexibility of controls. It features feed- back throughout, separate turnover and roll-off record compensators, new loud- ness control, wide range bass and treble controls, rumble and scratch filters, and six inputs including tape head. Fre- quency Response: *0.5 DB. 20 to 30,000 CPS. Distortion: 1% harmonic and 2% intermodulation at 12 watts.
20PG 20 Watt
An all new amplifier featuring new styling, advanced circuitry and greater control flexibility. The 20PG incorpor- ates feedback throughout and has all the new features of the deluxe 15PG plus higher power in the output stage. Frequency Response: +0.5 DB. 15 to 30,000 CPS. Distortion: 1% harmonic and 2% intermodulation at 20 watts. Cabinet in charcoal gray with brushed brass trim and front panel.
Net Price to user
GRT-3 HIGH FIDELITY FM-AM TUNER—A matching FM-AM Tuner for Grommes amplifiers and pre-amplifiers. Tuning is simplified by flywheel drive, tuning meter and AFC on FM. Circuit consists of tuned RF stage on FM and AM, dual limiters, wide band IF coils with high sensitivity and cathode
follower audio stage. Net Price to user
See the Grommes Hi-Fi Dealer in your area or write
Ask your dealer to also show you the Grommes Premier 212, a new deluxe equalizer pre-amplifier control center and the Premier 260, a new 60 watt basic amplifier. If your dealer cannot help you, write for complete details and where to buy.
Grommes Div. of Precision Electronics, Inc. Dept. R-1, 9101 King Avenue Franklin Park, Illinois
{_] Send Free Hi-Fi Equipment Brochure.
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143
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Certified Record Revue (Continued from page 70)
I have always championed the Toscanini reading of this work. While I still feel that it is one of the great performances on LP, I feel equally enamoured of the Paray version, and with the infinitely superior sound he is afforded, the totality of effect is stunning. Paray was a friend of Debussy and he has always had a particular affection for the great Frenchman’s music. That this associa- tion with Debussy has influenced Paray’s readings of his scores there can be little doubt, and purportedly Paray conducts these three works in accordance with Debussy’s intentions. If we accept this as a truism, we must then conclude that Toscanini’s reading is a much more “personal” thing than we had supposed. At any rate, while the Toscanini and Paray readings have a degree of sameness there are many aspects of the score at which they are at variance with each other. If you generally favor the ardes and intensity of the Toscanini interpretations, after listening to this you would probably not change your views. The Paray hes plenty of virility, but his approach is more linear than Toscanini’s. There is considerably more lyricism in his view of the score and he essays a gradual build-up in the tensions of the work until the turbulent finale where he gives his men full rein and the orchestra blazes with excitement In the “Prelude”, Paray displays exquisite taste in phrasing and balance and his is the most lyrical approach. His only serious com- petition is the Inghelbrecht and Munch read- ings, and while these are estimable record- ings they don’t quite achieve the high level of inspiration with which Paray infuses his ef- fort. Paray’s “Iberia” is really a remarkable musical document. He manages the difficult task of keeping an over-all lyrical feeling in the score, as in the other works . . . and at the same time the rhythmic sections are re- lentlessly propulsive, a lavish but controlled outpouring of musical energy that I find quite irresistible. The word for his reading is exciting! Soundwise, this recording is quite a few steps ahead of any competing versions. With the almost universal affection with which these works are regarded, I can predict that with the exalted sound they are afforded this will be a very big seller for Mercury. From every respect of frequency response, dynamic range, transient response, orchestral balance, acoustics . . . this recording is the most! The important string work, the inter- play of the first and second violins, the celli and contrabassi are all heard with crisp deti- nition. The woodwinds which lend so much color to these Debussy scores are superbly articulate, yet have a mellow richness which is a lovely thing to hear. Brass is weighty, but sparkling in detail. Percussion which is the soul of “Iberia” is sharply graven and its transient contour faultlessly clean. The so- norous impact of the opening bars of “Iberia” is fabulous and sets a whole mood of expect- ant excitement. Best of all, remember as you listen to this wonderful recording of “Iberia” that some day, not too far distant, you'll be able to hear it in the matchless glory of three- channel stereophonic sound. I’ve heard it and the experience is beyond description.
BEETHOVEN
SYMPHONY #6 (PASTORALE) Boston Symphony Orchestra conducted by Charles Munch. Victor LM-1997. RIAA curve. Price $3.98.
With 16 previous recordings of this work in the LP catalogue, this 17th version does not stimulate me to take offense at duplication, but rather I protest that inundation is the
more appropriate term! Still, everyone wants to get into the act and I suppose we will eventually get immured to the idea. Munch’s contribution is a fairly straight-forward ex- position of the “Pastorale” . .. a good unpre- tentious reading, somewhat lacking in poetry and drama, but clean of line and never overly fussy. The magnificent playing of the Boston men is one of the larger attractions, as is the sound which is well balanced, wide in fre- quency, dynamics, and with persuasively “live” acoustics. One cheering thought .. . this will probably soon be issued as a two- channel stereo!
STRAVINSKY
SONG OF THE NIGHTINGALE
(SYMPHONIC POEM)
PULCINELLA SUITE L’Orchestre de la Suisse Romande con- ducted by Ernest Ansermet. London LL1494. RIAA curve. Price $3.98.
The “Song of the Nightingale” is a sym- phonic poem or suite made up of music from Stravinsky’s opera “Le Rossignol.” The fine Angel recording of the opera was reviewed in these pages recently and for those people who may have been fascinated by the music but who found the singing and the French dialogue hard to digest . . . this purely orches- tral version should be particularly welcome. Ansermet is at the top of his form in this work and his interpretation gives ample evi- dence that his reputation as one of the great conductors of Stravinsky’s music is well de- served. The Pulcinella recording is interesting to compare with Stravinsky’s own perform- ance on a Columbia LP. Ansermet essays a slighter slower pace than does Stravinsky and generally does not get as much “zip or bounce” in his reading. Otherwise, Anser- met’s ideas are remarkably parallel with Stra- vinsky. There is a wider gulf between the two recordings in matter of sound quality. The Columbia disc has modern wide-range sound, with excellent orchestral balance, and a full-bodied string tone. On the negative side, it has excessive pre- and post-groove echo. The London disc is a real whiz. The over-all sound has a much smoother, more refined quality than the coarser Columbia. In the highly atmospheric “Song of the Nightingale,” there is a great variety of per- cussion . . . some of which is very subtle and a challenge to the powers of definition of any hi-fi system. All told, with the fine play- ing Ansermet elicits from his men and the fascinating subject matter, this is one of the most highly listenable recordings in recent months.
BACH
THE SIX CLAVIER PARTITAS
(CLAVIERUBUNG VOLUME 1)
Agi Jambor, pianist. Capitol PBR8344. RIAA curve. Price $7.96. Two dises.
This is Capitol’s first multiple record album and they are to be commended for their courage in issuing something as relatively esoteric as these Bach “Partitas.” Mme. Jam- bor is a most sensitive and perceptive artist of considerable taste and objectivity. If she chooses to use the piano as her vehicle rather than the harpsichord, that is her concern, and we should not arbitrarily place a stigma on her for lack of authenticity. Admittedly the splendid Haydn Society version with Kirk- patrick at the harpsichord is a model of con- formation, and good as Mme. Jambor is, she does not yet challenge the stature of a Kirk- patrick. However, her performance is com- pletely honest, and if she can conquer a cer- tain reticence in her playing and imbue the score with more warmth, hers will be a talent worth watching. The sound the Capitol en- gineers afford her is of a magnificence that more than atones for her minor sins of per- formance. One of the most beautifully natu- ral-sounding piano recordings yet made .. .
RADIO & TELEVISION NEWS
excepti in its | soundir chaste
RAVE BO! RH.
LA DEBU
PRI A Boston by Ch RIAA
“The aptly ti Boston Charles repertoi indicate merely orchestr There ° hurl th formans one wot “Prelud for my sodie E: forman is surp reading. efforts y an inte overwhe dynami and unl spective realism string c smoothr measure: beyond Boston thing né processit cutterhe: thing. , recordin; logue an
GRIEG PIAN RCA Sy
lenstein
LISZT CON RCA Sy
lenstein
Price $7
Once a which m um” to d tur Rube piano wo Artur Ru touchable though tl sessions is exalted pl stein coul Wallenste Grieg and hearsal ti can do be cap, Rube that fant:
January,
exceptional in its clean delineation, pristine in its transient response, wonderfully “live” sounding in the felicitous acoustics and the chaste quietness of the surfaces.
RAVEL
BOLERO
RHAPSODIE ESPAGNOLE
LA VALSE DEBUSSY
PRELUDE TO THE AFTERNOON OF
A FAUN
Boston Symphony Orchestra conducted by Charles Munch. Victor LM-1984. RIAA curve. Price $3.98.
“The Virtuoso Orchestra,” as this disc is so aptly titled, is intended as a showcase for the Boston Symphony Orchestra and conductor Charles Munch’s proclivities for the colorful repertoire of his native France. As the titles indicate, there is nothing new here, the works merely serving as vehicles for an amazing orchestral and conductorial tour de force. There will undoubtedly be some who will hurl the epithet “overblown” at these per- formances and sound, but I don’t think any- one would deny that they are exciting! The “Prelude” is well done but too slow-paced for my taste .. . the “Bolero” and “Rhap- sodie Espagnole” rank with the very best per- formances on record, and Munch’s “La Valse” is surpassed only by the towering Paray reading. The sound here is one of the best efforts yet by Victor. There is a taut urgency, an intensity in the sound, that is almost overwhelming. Very wide in frequency and dynamic range, the transient response clean and unbridled, and a spacious acoustic per- spective, all contribute to the outstanding realism of the sound. The definition of the string choirs, the punchy brass, the famed smoothness of the Boston woodwinds, and the measured impact of the percussion are quite beyond previous listening experience with the Boston group. One wonders, in fact, if “some- thing new has been added,” to the Victor processing armamentarium . like a new cutterhead or cutter amplifier, or some such thing. At any rate, one of the very best recordings in the whole of the Victor cata- logue and highly recommended.
GRIEG PIANO CONCERTO IN A MINOR RCA Symphony Orchestra, Alfred Wal-
lenstein conducting.
LISZT CONCERTO #1 IN E FLAT RCA Symphony Orchestra, Alfred Wal-
lenstein conducting.
RACHMANINOFF CONCERTO #2 RHAPSODIE ON A THEME OF PAGANINI Chicago Symphony Orchestra, Fritz Reiner conducting.
Artur Rubenstein, pianist in each selec- |
tion. Victor LM-6039. RIAA curve.
Price $7.96. Two dises.
Once again a generic title, “The Concerto”, which merely serves as a “packaging medi- um” to display the prowess of the great Ar- tur Rubenstein, in four of the most popular piano works in the concert repertoire. When Artur Rubenstein is “right,” he is literally un- touchable in quality of performance, and al- though the work of two different recording sessions is in this album, his playing is on an exalted plane in both. It is a pity that Ruben- stein could not have had better support from Wallenstein, whose accompaniment in the Grieg and Liszt was quite ragged. Lack of re- hearsal time, perhaps? I know Wallenstein can do better than this. In spite of his handi- cap, Rubenstein runs through the works with that fantastic grace, that assured composure
January, 1957
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NOT EVERYONE APPRECIATES THE HARTLEY
It is a proven, scientific fact thet musical sounds DISCRIMINATE, They give more lis- tening pleasure to one person thon any other, due to the ability of some blessed ears to hear true pitch. Those of you who belong to this fortunate group will truly understand and appreciate the greatness that is the Hartley 215 Speaker system.
THE SPEAKER THAT PRODUCES NO SOUND
Whether it be a fanfare of trumpets or the roll of a drum, the sound of the instruments —nothing else—comes through the Hartley Speaker system. It is free from resonance— free from distortion. Laboratory tests con- firm this statement.
REALISTIC HIGH FIDELITY
Substitute a Hartley 215 in any system and immediately you will hear the amazing difference. Designed by H. A. Hartley, famous audio consultant, it will provide you with the best sound reproduction possible, outperforming speakers of larger size.
Hartley 215 Speaker Systems
The renowned Hartley Boffle, with one, two, three or four drivers. Prices start at $115.75 for the complete system. At franchised dealers or write for details:
HARTLEY PRODUCTS CO. DEPT. 20 « 521 East 162nd Street New York 51, N. Y.
LUdlow 5-4239
Now available at:
Grand Central Radio 124 East 44th St. New York, N. Y.
Listening Post 2290 Fillmore St. San Francisco, Calif.
Rabson’s Olin S. Grove 119 W. 57th St. 2904 Telegraph Ave. New York, N. Y. Oakland, Calif,
| that marks his best efforts. It is a different
story in the Reiner sessions where a most
| splendid rapport is much in evidence. With | the richly sonorous, ultra-precise Chicago or-
chestra aiding and abetting him, Rubenstein
| makes of the two Rachmaninoff works testi- | monial of his incredible skill . . . a sonic legacy
that probably will be studied in later years as models of their kind. It is difficult to conceive of a more positive statement on the Rach- maninoff works than Rubenstein here affords. The fire and dash of his technical brilliance, the compelling warmth and depth of feeling with which he imbues his traversal of the
| scores, all add up to an unforgettable musical
experience. Soundwise, the Wallenstein ses- sions are good but unspectacular and not par- ticularly distinguished. The Reiner sessions, on the other hand, are noteworthy for the splendid balance between piano and orches- tra, the magnificent huge “liveness” of the piano tone afforded by the extraordinary acoustics of Orchestra Hall, the clarity and weight of the rich orchestral fabric. Don’t fail to hear this album!
MARCHES FOR TWIRLING Frederick Fenell conducting Eastman Symphonic Wind Ensemble. Mercury MG 50113. RIAA curve. Price $3.98.
I’ve about run out of superlatives for Fred Fennell and his fabulous band recordings. If you like the measured tromp of marching feet, the color and gaiety of a parade, the splendid brazen voice of a mighty band, you can’t fail to like the series of band record- ings he has made for Mercury. This is the latest and one of the greatest and the reper- toire should appeal to just about everyone. Band-King Sousa is represented by four of his pulse stirrin’ specials, these being the “Stars and Stripes Forever,” “The U. S. Field Artillery,” “Semper Fidelis,” and “Manhattan Beach.” Among other favorites are Bagley’s “National Emblem,” Goldman’s “On the Mall,” and Bigelow’s “Our Director.” As
| usual the fidelity is positively hair-raisin’,
with the OOM-PAH of the brass, the multi- hued voices of the woodwind, the soul-satis- fyin’ WHUMP of the bass drum, and shat- tering impact of cymbal reproduced with maximum articulation and lack of transient distortion. Dynamic range is almost danger- ously extreme for some of the cheaper, poorly balanced phonograph pickups. Given top-
| notch equipment and a big speaker system,
when played at the pyschological approxima- tion of concert-hall level, this will shake the fillings out of your teeth!
SCHUMANN PIANO CONCERTO IN A MINOR SCENES FROM CHILDHOOD
| Walter Gieseking, pianist. Herbert von | Karajan conducting Philharmonia Or-
chestra. Angel 35321. RIAA curve. Price $4.98.
For my money, this is the best Schumann
| Concerto since the late Dinu Lipatti’s reading
on an early Columbia LP. It is true that age
| has made some inroads on the technical com-
mand of Gieseking . . . he misses notes here
|-and there, and commits other minor flubs.
But one can forgive these occasional lapses
| for the privilege of hearing this Concerto | come to life with Gieseking’s remarkable in-
sight and understanding of the score. One
| can savor his delicate phrasing, his brilliant
play on dynamics, the care he lavishes on seeming minutae, and the still greater care that these details do not become fussiness, nor his approach too pedantic. Karajan furnishes a most sympathetic accompaniment, and under his urgings the splendid Philhar- monia responds with playing of great warmth and precision. In the “Kinderscenen,” Giese- king has competition from several other fine
| artists, notably Novaes and Curzon, but still
makes off with top honors. Soundwise, the recording is good but not outstanding. Some- how it all seems a little cramped and does not have the usual open fullness typical of Angel concerto recordings. Piano and string tone per se are fine, everything is quite clean and near distortionless. In the over-all view, the restriction on the sound is noticeable but it’s not so obtrusive that you can’t lose yourself in the excellence of the performance and en- joy yourself quite thoroughly.
Stereophonic Tape
BACH
BRANDENBURG CONCERTOS
(COMPLETE )
Jascha Horenstein conducting anony- mous orchestra and soloists. Phonotapes Sonore PM136. Two 7” reels, half track, 7% ips. NARTB curve. Price $13.90.
This is presumably the first two-reel tape release in the pre-recorded tape field. Cer- tainly the “Brandenburg Concertos” would have to be issued in this format because of their length. The tape box is very cleverly designed so that when closed it has minimum bulk and looks like a somewhat obese single tape box, yet it contains the two tapes quite neatly and with a maximum of protection. The performances are quite good and, of course, have been widely admired when they were originally issued on Vox Records. The sound of the disc was quite good and these tapes are more so by a considerable margin. One notices the immediate improvement of inner detail, quite important in the “Bran- denburg,” the improved transient response, and the enhancement of the dynamic range. Frequency response appears to extend to the upper limits of the spectrum and I partic- ularly listened for “blast overload” distortion in the brass parts, a common failing both in records and tape when Bach trumpets are played hard in the higher registers, and this effect was quite minimal. Hiss was notice- able but not obtrusive.
MOTORBOATING IN A TRANSISTOR PORTABLE
By JAMES A. McROBERTS
N RCA Victor transistor portable
(Model 7-BT-9J) developed motor-
boating on reasonably loud sound pas- sages.
The cure consisted of installing an additional bypass capacitor of 50 fd., 25 volt rating across the power bus and chassis. The “hot” power bus is posi- tive in this set. Due to compactness of the unit, the added capacitor was in- stalled over the existing capacitor C., near the output stage.
As the partial schematic below shows, the added 50 ufd. capacitor is a bypass on the final audio stage (class B) which has large fluctuations of current drawn from the battery. For most sets, the de- coupling filter of Rw (100 ohms) and Cy; (45 ufd.) suffice to keep the second audio ripple out of the preceeding audio stage and the remainder of the set. The filter and the inherent filtering action of the battery was not sufficient in this instance, however.
RADIO & TELEVISION NEWS
Twe
the in Full b be ob this sy For ceram this p equaili: speake what unit i was fi compe and, il at low justm« corres tion b systen pickuf Wit! scribe to say on a not ar haps langue sume fore. lost ir bass. bass. vibran descrij very | notes. take o It is the a said t they n the sir like ¢ Tone | other | essent. ever t tion o this s dental ear’s I crosso’ of fre eral o ent of effect | contro To j contro high-f1 ates al been k But i
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Januar
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Two-Way Speaker Operation (Continued from page 50)
the improvement may prove startling. Full benefit from the possibilities may be obtained only with the flexibility this system affords.
For these experiments a wide-range ceramic pickup was used and although this pickup is not required to have equalization and the ‘low-frequency speaker system was perhaps some- what better than average (a 15-inch unit in a 12-cubic foot enclosure), it was found that a full 20 db of bass compensation was not at all excessive and, in fact, was enormously pleasing at low volume levels with proper ad- justment of high-frequency gain. This corresponds to 20 db of bass equaliza- tion beyond that ordinarily present in systems using a constant velocity pickup.
With this system, operated as de- scribed, it is no mere figure of speech to say that the reproduced music takes on a “dimensional” quality. This is not an apt description, but it is per- haps the nearest approximation the language affords. Individual notes as- sume an identity they never had be- fore. Even faint, high ones are not lost in the shuffle or masked by the bass. There is no way to describe the bass. Every note stands out, with a vibrantly realistic quality that defies description, but strangely even when very loud, does not mask the high notes. All notes, of whatever pitch, take on added luster.
It is interesting to note that while the amplifier gain controls may be said to act as tone controls in that they modify frequency response, there the similarity ends. Their effect is un- like any conventional tone control. Tone controls roll off one end or the other of the range and are, therefore, essentially. restrictive devices, what- ever they may be called. But opera- tion of the separate gain controls in this system is restrictive only inci- dentally (and is a result either of the ear’s nonlinearity or proximity of the crossover point) from the standpoint of frequency. Even so, it affects sev- eral octaves uniformly and independ- ent of frequency, a radically different effect than that of a conventional tone control.
To illustrate, operation of a treble control so that noticeable roll-off of high-frequency response occurs, cre- ates an impression that something has been lost, a quite accurate impression. But in this system reproduction of high-frequency gain, within reason- able limits, of course, creates no such impression. Nothing has been lost, one feels. It has merely moved away from you.
A master gain control in addition to the individual ones would be a con- venience, but since its design would depend on many variable factors, it has not been incorporated in the schematic shown.
January, 1957
A R K AY nits. . . ee moll.
wewl ANOTHER ARKAY WINNER!!
SPECIFICATIONS: POWER—30 watts @ 1% IM. FREQ. RESPONSE +¥2 db.—20- 50,000 cps. HUM—120 db. below rated out- put. Actually zero. CONTROLS—(6) Func. selector, loud- ness, bass, treble, level set, 5-posi- tion level compensation control. @ 2 EL-34/6CA7 Super-Lin Williamson © Special Output for Simultaneous Tape Recording and Monitoring
’ . - :
—
ARKAY Model FL-30 Hi-Fi AMP-PRE-AMP
Featuring a transistorized front end for use with a reluctance pick-up, this engineering masterpiece assures the finest in HI-Fl repro- duction for more than 30 labels (LP, RIAA, & EUR). Complete with rose gold panel and black cabinet.
a0
Speaker
” HiFi AMPLIFIER
A super lin. Williamson 12-
| FL-0 | H
e 4 Ps
watt Hi-Fi amplifier with built- 3 in pre-amp. 18 watt peak with
f a frequency response of 20- 40,000 cps. 4 controls includ ing record equalization (LP,
# RIAA, EUR). Output imped- = ances, 4, 8, & 16 ohms. Spe- : cial output for simultaneous
tape recording and monitoring.
4 UV sensitivity for 30 db.
; quieting. AFC with provisions ; for erase. Allows pinpoint,
high selectivity tuning. Foster- Seeley discriminator, high effi- ciency AM loop stick antenna and temperature compensated oscillator circuit. Built in
transformer operated power :
supply. Now! Wired & Tested $49.95
Kit Less Cover $32.00 3
Cover for Above $3.95 Fed. Ex. Tax Incl
System Frequency Response: 10 to 20,000 cps. Crossover Fre- quency: 1600 cps. Power Rat- ing: 25 watts. Impedance 16 ohms. Features a bass reflex, ducted port enclosure equip- ped with a low frequency speaker and a compression driven horn of special design. A variable balance contro! w/ network provides smooth con- tinuous adjustment of the H/F speaker. ... $
ARKAY RADIOS
Arkay manufactures a com-
plete line of radios unmatched in the industry in quality and performance. They include: transistor portables, table models, multiband receivers, portables, and many other models. There is certain to be one to fit your requirements.
g ET THE NEW, BIG CATALO FREE ARKAY LINE—NOW AT YOUR LOCAL DEALER! e Prices 5%, higher West of the Mississippi
4 UV sensitivity for 30 db. quieting, A.F.C... . grounded grid front-end; Foster-Seeley Discriminator. Temperature compensated oscillator circuit. 4 double tuned IF stages, limiter and discriminator give top selectivity and sensitivity. Built-in transformer operated power supply
Fed. Tax incl.
ARKAY Model 14721 new! TV KIT
Very latest design used in sync. circuits results in ex- cellent stability with extreme- ly low noise characteristics. A. G. C. circuit résults in max- imum sync. hold characteris- tics. The only vertical ,chassis construction, series-string- heater type tubes, vertical re- trace blanking circuits, and many more features. $79 50
EASY 10
It is easy to learn or increase speed with an Instructograph Code Teacher. Affords the quickest and most prac- tical method yet developed. For be
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RUMBLE: for E 53 N motor mounted on CD-43, CBA-83, CB-33 and E-53PA units. (Reference level: 2.6 cm/sec., 1000 cps.)
Total 100 low
rumble cycle frequency level rumble rumble Best units.......—52 db. —53 db. —55 db. —50 db. —51 db. —53 db. Lower limit for all units equipped —48 db. —49 db. —52 db. with E 53.N motors
FLUTTER: Less than (0.1%.
WOW: Less than 0.3%. Tests made with the standard 12” turn- table weighing 2% Ibs.
These measurements are minimum quality control standards which must be met or exceeded by every THORENS RECORD CHANGER, PLAYER AND TURNTABLE!
ask your dealer to
demonstrate THORENS
Write for Thorens Catalog.
Realistic High Fidelity (Continued from page 66)
is that portion of the output volts fed back to the input. It is usually given the Greek letter beta, 8. Obviously 8 cannot be greater than unity, and if there is no feedback then it equals 0. If the gain of the amplifier is expressed in db, then 8 can be expressed in db. If we call the amplification of the amplifier A, without feedback, then the amplification after feedback is A/(1+ 8A). You may find this formu- la in textbooks with the sign in the denominator negative, but if it is neg- ative feedback then 8 carries a nega- tive sign itself, so my formula is finally correct. If in this formula you call A distortion or output tube plate resist- ance, these parameters are reduced by the same amount. So negative feed- back reduces gain, distortion, and the effective plate resistance of the output tubes.
Reducing gain seems a futile sort of thing to do but it is quite important. In the absence of feedback the ampli- fier will have a certain frequency re- sponse, and it will tail off in the bass and treble. If, now, negative feedback is applied, it will be clear that less voltage will be fed back in the bass and treble simply because the output voltage is less, so there will be less loss of gain at each end of the fre- quency response and the feedback am- plifier will show a wider flat response than the original. It sounds wonder- ful, which is why it is used so fre- quently, but now creeps in a very se- rious liability.
Change of phase occurs in every tube and every RC coupling. With tri- ode output stages more amplification is needed than with tetrodes or pen- todes, perhaps even to the extent of having to provide an extra stage to do it. At any rate the phase change in a multi-stage amplifier can become so progressively great that the negative feedback is changed into positive feed- back and the amplifier becomes un- stable.
Take only the bass roll-off in an or- dinary RC amplifier. This usually re- sults from a short time-constant in the interstage couplings and inadequate bypass capacitors. A generously de- signed amplifier not only uses large plate-grid capacitors but large bypass capacitors and a_ time-constant is chosen to avoid bass roll-off. Now it can be shown mathematically and ex- perimentally that the conditions which cause bass roll-off cause large phase change. If, therefore, negative feed- back is used to compensate bass loss, phase change may convert it into posi- tive feedback. An indifferent amplifier can therefore be made better only by using limited feedback, and the final result will be less good than an orig- inally well designed amplifier without feedback.
Remember this golden rule at all times: negative feedback is of real
service only to an amplifier that is very good without feedback.
Unfortunately a further complica- tion now arises. Suppose you want to use a lot of feedback to reduce the output plate resistance (and conse- quently improve the damping factor). Your good amplifier has a fine bass re- sponse, even if it has several stages of amplification. Let us suppose that it is flat down to 20 cps and then rolls off to 2 cps. The phase shift at the lowest frequencies will be so great that you cannot use the amount of feedback you would like, and the am- plifier will motorboat. The ideal am- plifier for use with negative feedback must be provided with a _ response which absolutely cuts off all frequen- cies below a certain useful point. There are parallel arguments for the treble end, too, which need not be considered at this stage; I need only say that your basic good amplifier must have a level and undistorted response (within reason, of course) between the pre- determined limits, and then cut off abruptly in both bass and treble by in- cluding suitably designed step circuits. (See Fig. 36.) Then, and only then, you can apply negative feedback and make a fine job better.
Negative feedback cannot increase the undistorted output of any power stage. If an amplifier without feed- back gives, say, 10 watts with 2% dis- tortion, application of negative feed- back may reduce the distortion to 0.5% but if, as a result of the de- creased gain you boost the input in the hope of getting more than 10 watts with 2% distortion you will find it is not possible. A simple demon- stration will prove this.
Use an audio oscillator to drive your amplifier and with a resistive load on the output transformer secondary to equal the speaker impedance marked on the transformer, connect an oscillo- scope across the load. Set the oscil- lator to any frequency you like, but 1000 cps is a very safe one. Any am- plifier ought to be able to handle that frequency without distortion. Discon- nect the feedback circuit. If there is variable feedback, so much the better. Using a sine-wave input, adjust the volume control until the tube picture is just not flat-topping, and note the height of the trace above the datum line. If you increase the input or turn up the volume control, the sine wave will now take on a flat top, getting a wider flat as you increase the signal to the output stage, but the trace won’t get any higher.
Now connect the feedback circuit. The flat top will disappear because you have reduced the gain of the am- plifier and so the output stage is not overloaded. You can increase the input until the flat top is on the point of appearing again, and if you have vari- able feedback you can increase the in- put still more and cut out the flat top by increasing feedback. But you can’t heighten the trace. In other words, you can’t get more power out of the tubes.
RADIO & TELEVISION NEWS
Fig. 37. Oscillograms illustrating the effects of negative feedback.
Fig. 37 shows tracings from an oscil- loscope screen. Fig. 37A shows several cycles of a sine wave. These are too crowded since the sides appear to be nearly straight. Use the horizontal am- plifier in the scope to widen the trace so that it looks like Fig. 37B. It can now be seen that no part of a sine wave is a straight line. Fig. 37C shows three sine waves; the dashed trace shows a rather small amplifier output, the solid trace the full undistorted out- put of the amplifier. If the output is further increased, the tops and bot- toms of each cycle will be flattened, as shown solid in Fig. 37D. The sides seem to be straight but this is only an illusion similar to that in Fig. 37A. To compensate for the increased vertical amplitude (the dotted peaks in Fig. 37D show what the trace would be like with a larger output stage) the horizontal amplitude should be propor- tionately increased to simulate the conditions of Fig. 37B. Applying neg- ative feedback to Fig. 37D will reduce the vertical amplitude and return it to conditions shown at Fig. 37C. Fig. 37E shows one cycle of a pure sine wave. If negative feedback is used to get slightly more output before flat-top- ping begins, the trace of Fig. 37E will be changed to that shown in Fig. 37F. The dotted horizontal lines indicate the height of Fig. 37E transferred to Fig. 37F. The gain is slight and the sides are straighter.
It is sometimes rather difficult to spot the divergence from a pure sine wave of the trace on a small tube. The fed-back distortion cleans up the wave shape but when maximum undistorted power is reached and further input or volume (gain) is applied there will be a very slight increase of height with feedback and the waveform will look sinusoidal; actually, however, the sides of the wave will be slightly straighter, implying some _ distortion. Without feedback the change in waveform is rather gentle until flat-topping starts, and it may be thought that the ampli- fier is performing better than it really is. With feedback the shape is seen to change quite suddenly. Feedback, therefore, reduces distortion before overloading starts, but the overload point is reached suddenly, from a prac- tical point of view, with no greater output than that obtainable from an amplifier without feedback.
January, 1957 149
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The unidirectional dynamic Unidynes are now more than ever your best choice in those installations where feedback is a problem, and for all fine-quality public address, theatre-stage sound systems, magnetic recording and remote broad- casting—where critical standards call for the finest-quality microphone operation.
Another example of the continuous creativity of the Shure Research and Development Laboratories.
55S Unidyne List Price $7950 556S Broadcast Unidyne List Price $120°° IN ELECTRONICS SINCE 1925
Fhe Mo f Ql
SHURE BROTHERS, INC.
Microphones ~= Electronic Components
210 HARTREY AVENUE -
EVANSTON, ILLINOIS
aera SS Sent lterwrr aro
The characteristics of the power out- put stage will be discussed more fully in the next article. For the moment it need just be pointed out that negative feedback, by reducing the effective plate resistance of the output tubes, provides a more favorable load imped- ance/plate resistance factor, thus im- proving the speaker damping factor and making tetrodes and pentodes | more like triodes without impairing Twenty-four leading phono pickups have now been tested by The Audio 1 al gots OS 4 League. The ESL Professional and Concert Series remain in first place: | here is that the power output figures
given in the tube manuals presuppose These Audio League tests show that ESL electrodynamic cartridges | the use of a pure resistive load, and
: , naturalness of revroduction.* the load lines drawn on the character- are tops i smoothness, clarity, and f ? istic curves are straight lines. The dis-
In addition, record and stylus life are greatly extended by the ESL, ries eta need taethote sar geng Da which in this way saves the purchaser many times its own Cost. | formed by an output transformer and : | speaker is not a pure resistive load but Join the musicians, engineers, and music lovers who have switched to the | a reactive one. This has to be shown world’s most advanced cartridge. Write for details and, even better, on the curves as an ellipse. The impli- : - cations of this may not be quite clear hear the difference at your dealer's. | to you for the moment, but it does mean that a reactive load reduces the | undistorted output from the stage as compared with that obtained with a
FOR LISTENING AT ITS BEST pure resistive load. All these factors I have described
H : I have to be taken into account when Electro-Sonic Laboratories, nC. considering the accuracy of my 3, 6, and 11-watt postulates. These are peak undistorted outputs and the mean out- put will be considerably less than that. Soloist Series from $14.95 « Concert Series $35.95 + Professional Series arm and cartridge $106.50 | But we have no room for distortion on
peaks when providing realistic sound
* Authorized quotation No. 57. Please consult The Audio League Report, Vol. 1, No. 6-7 (March-April 1955) reproduction; it must be undistorted
for the complete technical and subjective report. Subscription: 1 2 issues $4, from P. O. Box 262, Mt. Vernon,N.Y. | all the time. To provide a safety mar-
| ———~ | gin to take care of all the extraneous sources of distortion the simplest way
‘ THE VERY BEST IN CUSTOM TELEVISION is to use a bigger output stage and the 4 margin I would suggest is 100%. So
f. h sy TECH-MASTER my figures for the three types of
Dept. R + 35-54 Thirty-sixth Street « Long Island City 6, N.Y.
Vv o
speakers first mentioned are, roughly, 7, 15, and 25 watts.
The danger is that with the extra power you may be tempted to run the volume a little louder than necessary and get distortion on peaks. Many equipments sound bad because they are overdriven, not because they are inherently bad.
(To be continued)
COGWHEEL EFFECT
By JAMES A. McROBERTS HE Zenith 19L25 chassis displayed the wavering circles on the test pattern and in the pictures which are characteristics of the “cogwheel” effect. The 1 megohm
il “eS . resistor (Rz) connected between pins 1
FOUND IN THE FINEST OF INTERIORS vo a and 2 of the 6AQ7GT had changed value FE to 1.5 megohm. Since this was originally
aha m a + 10% resistor, the resultant unbal-
ance in the horizontal a.f.c. circuit
As the custom installation signifies the ultimate in : S| caused t.te hunt or epeiliaee abent the
well-chosen decor ...so the name Tech-Master horizontal oscillator frequency so that stands for the utmost in Custom television. The | —_ f | the cogwheel or picerust effect would : : F bea cedleci occur whenever an appreciable frequency reputation established with the manufacture of the coay Techsaseen difference existed between the incoming renowned Model 630 chassis is further enhanced was THESE OUTSTANDING fomume” local horizontal oscillator by the outstanding Tech-Master Audiophile and PLUS FEATURES: When replacing resistor Rx, note that Sound Theatre © World-famous 3 tube synchro- it has a mate, also labelled Rx between ; po ge FS re og pins 2 (cathode) and 3 (another diode
. 3 ily used. © “Full Frame Mount- | Plate) of the 6AQ7GT. These two resistors
See your Custom hi-fi dealer today .. . or write ting” ... justa ingle atest should be equal in value rather than TECH-MASTER CORPORATION pine ge Rp reece“ arbitrarily 1 megohm, + 10%, so select 75 FRONT STREET, BROOKLYN, NEW YORK exceptional audio reproduction. | for balance rather than tolerance. —3Q-
150 RADIO & TELEVISION NEWS
MDF-82 for exact replacement in over 30 DUMONT models and chassis; equipped with octal plug and ground clamp. Another in the complete line of exact transformers, yokes and coils. Merit is the only manufacturer of transformers, yokes and coils who has complete production facilities for all parts sold under their brand name.
MERIT
MERIT COIL AND TRANSFORMER CORP.
January, 1957
210 HARTREY AVENUE
What's New in Radio
TRANSISTOR RADIO KIT
Tran-kit Electronics, 467 South 5th Ave., Mt. Vernon, N. Y., has announced a new addition to its line of transis- torized radio kits.
The Model TK-104 superhet uses four transistors and is completely subminiaturized. The circuit is con- structed on a printed circuit board. The unit measures only 6”x 4" x2”.
The self-contained speaker delivers 18 |
milliwatts and an external phone jack
cuts out the speaker when the ear- |
phone is plugged in. The kit, including a Texon leather
case, comes with complete and detailed
assembly instructions.
For full details on this and other kits in the company’s line, write Dept. PR of the firm.
LOW-COST METER RELAYS
Simpson Electric Company, 5200 W. |
Kinzie St., Chicago 44, Ill, is now offering a new and improved series of low-cost meter relays which feature a simplified design with platinum alloy
contacts and increased contact force. | Operating on power inputs of less |
than 50 millimicrowatts, the new re- lays will control up to one watt, a power amplification of 20 million
times, The new units should find wide |
use in many special applications as
well as standard alarm, control, and | limit-setting circuits, where it has not
been feasible to use meter relays here- tofore. The relays are a non-locking type,
currently available in 2” d.c. and 3” | a.c.-d.c. models as microammeters, mil- |
liammeters, ammeters, millivoltmeters,
and voltmeters. Pyrometer types with |
bimetal compensation are also avail- able.
SUPEREX TRANSISTOR KIT Superex Electronics Corp., 4-6 Rad-
ford Place, Yonkers, N. Y., is in pro- | duction on a new transistor radio kit | which features advanced circuitry and | uses two penlight batteries for power. |
The radio will give loudspeaker re- ception in good locations. The design features a printed circuit, matched transistors and a diode, a “Loopstick,”
151
¢ EVANSTON, ILLINOIS
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LOWEST COST because our giant buying power passes biggest savings on to you...you do the easy assembly and your finished instrument. is equal in performance and appearance to equipment selling for several times the KNIGHT-KIT cost (Easy Payment Terms available, too.)
knight-kits
EASIEST TO BUILD because KNIGHT-KIT ‘Step-and-Chek" instruction manuals are marvels of clarity—it's just like having a good instructor at
your side. Proved professional design and premium quality parts help insure your building success.
~~ =, knight-kits MONEY-BACK GUARANTEE: When properly assembled, KNIGHT-KITS fully meet published specifications, or we refund your money.
WHEN YOU BUILD A KNIGHT-KIT
YOU BUILD THE BEST
NE
For a Complete Selection of
Famous knight-kits
SEE PAGES 105-111
Available Only From
ALLIED RADIO 100 N. Western Ave., Chicago 80, III.
RADIO & TELEVISION NEWS
rawr er SESS See VPS eS ee, TVS ye LF SASS Hore raes Sewer Fee
150
all housed in an unbreakable grey pu A poms é plastic case. rel n A 16-page instruction book is in- cluded with the kit and makes assem- the MB mi Choose the Isl amie: for best! te Me pe dit ulr cal tri Gases é a! , : dig 4. Modern Jazz: Modern ool Jazz: Great | | 6- Dixieland: Tiger Rag, |] 7. Swinging Jazz: Jo tul sounds by Mulligan, || sounds by Charlie other Dixieland clas- || Jones and Basie alum- a | others. Summertime, Parker and Stan Getz, }]] sics, with P. Barbarin, ni swing Embraceable I Hear Music, etc. kings of “modern” sax. | | J. McPartland. You, Caravan, ete. i ian i ts sey anne ‘ | ur INTRODUCE YOU to the Return any you don’t want. Pay only bly both easy and educational. Write qu superb artistry of these high- the special Members price of just the company for further details and fidelity jazz recordings, The ~ A ere aan ‘Jou save more price information pa Jazztone Society offers you amy than 35%. And you may resign any : ap] ba ey jazz concerts shown , aay genvine three selections —_—_—__ op above for onl $8! Not one uring the first year. x 3 ; record, but ec it tack quiet Don’t miss this opportunity to get I pep ae ROUND METER - 3. Big Band Jazz: Good- |] Surface, long-playing (3314 RPM) fot only 3 96, Mail the seuon today nternational Instruments Inc., New 68% man, Dorsey, Basie, vinyl recordings containing up -———— Haven 15, Conn., is now in production Shaw, St. Louis Baby, to 36 of the greatest jazz class- j The Jazztone Society, Dept. 3003 a on a new 1” round panel meter for pel Flat Foot Floogie, etc. ics ever recorded 71 Fifth Avenue, New York 3, N.Y flush mounting fai Send three Jazz Long-Play Albums - * . j A0 > Soe Digtes and circled below Designated as the Model 104, the e
All the Big Names “tts eee er Ss Se ee
If I keep them, I'll pay only $2.98 (plus shipping) for all three. Also, enroll me as a Trial Member. Privileges: advance notice of re- leases; 5 day free trial on any discs. 1 may reject records before or after hearing them; may can- cel membership any time after buying 3 monthly selections. Fu-
new instrument is said to provide the longest scale arc in the smallest pos- sible panel space. The unit is partic- ularly adapted to portable, airborne, and other similar equipment where a high degree of aCcuracy must be com-
Here are the outstanding jazzmen of our time—-interpreting all the im- Few ge ew You'll find the big- : ‘ Z jazz of Goodman and Dorsey,
4 cool sounds of Parker and Getz, 2. Intimate Jazz: The ixie d. soft, breathy voice of Lee Wiley sings My Romance, My Funny
Mulligan and many others, all on these superb Jazztone Society record-
ings.
Valentine, etc.
Little Earful” doing AUDITION, his greatest numbers.
How to Build a Great Jaz
Waller, the “Cheerful scribed in advance. You can in your own home, any or all the So-
ciety’s releases for five days! Lo-—~—-———————— =
ture 12” long-play discs only $2.98 each plus few cents shipping
For info. on Canadian service, address: 105 Bond St., Toronto 2, | Ont.
ee ee ee es ee ee ee
bined with minimum size and weight. The meter employs a miniaturized
Collection at Huge Cash Savings Name........+ Ladaupinanieacdite
With the albums. you'll also obtain ates d’Arsonval type movement and accu-
L Fun ‘In Jazz: Fats BR hy rid "gach 4 , racy is held to +3% of full-scale deflec- monthly selection will be de- CRF. cocvesccccvcssesrce State..... tion for d.c. instruments and +5% for
a.c. instruments. Complete information on this new meter line is available from the man-
; CHROME VANADIUM ; ufacturer on request. 29 Pc. DRILL SET paren Specially made for oe ae. e | MODULARIZED RADIO 3 drills’ Rardetsed "and precision grownd. to | R & D Electronic Laboratories, Inc., obtainable: "will easily and ‘leants “bite | | 21-28 45th Road, Long Island City, ‘oO ods, plastics, aluminum, . . : I iron andthe toughest steels. . Uneondl’ !| New York, is now offering a low- ona ily n “ or ous. rds of ¢ . . . . . | abe ings. Vull jobber length Sizes bs é4tns | | priced modularized radio receiver kit From /16” to 4 L ted « antity avai r ° ! of Bi this low price, 0, my NOW ped. $6.49 | | in which two modules do the work 80 available wit! ner Jown Shanks to fi . . $ aa drills, “In individual pocket roll, ppd. § ag of sixteen separate electrical parts. i ye : Hi - ; KIT if See Se | | crane win medio cokes ime ! Wire Gauge Drills | | sible ia the average ‘ex natok to ; NO AC source 1 vague dS ee a — . required | aluminum. Sprecis: m sr oo Bn ~~ cutting | me H " b tte y i rr. ggg el » p in By of satisfaction. A gai as long batter life because $49 assembled | wT ony. wie eam Sask . $5.40 ) fre ¢ pp. 9 of Transistors Only | Some,cot stove wate wit Bit a $695 | a $ gets ee FE. | 2 / 0 amen || 15¢ ea. for Finest Imported SS | bo starte j PRECISION PLIERS —e | ma © Flat Nose © Round Nose = | een ‘ |S Diaponl Cuter © Qne Side Fiat ga | io Lab & Service Instruments in 1 ; | | * Nippers | ; | JE =< Combines a transistorized VTvM with a precision | Hobpyists, NGRAPTSMEN. OF Al L KINDS! <x I | ao hg ge vital pay / ii) Senet takers ted = high quality soa J ss e instantaneous checking of VTVM readings ! cati * Ali ver a at pall hed to | tio’ (3) eliminates doubtful results often obtained with | smooth surfaces. Smooth working a VTVM joints with just the right tension. | N Completely self-contained. No AC ired; | even the most delicate objects in the, ,neid | : ‘ompie y sell-contained. oO power requ m4 e 8 lelicate objec n ie ha no vacuum tubes to go bad. Turn of switch con- to te 2 SS Se | bat = gg, MR ee a, cee (VOM | and strength. i er agains e ver sion parte F in kit, such as 1%" Resistors, Shunts, ‘Mien 75¢ ea. .all 7 hol “ ae A a : assemble the set in less than half an I Only $10 gets you started; balance in easy pay- | hour. There is little wiring to be done dio wet psec gapped ation: 5180 | PRECISION "SGiEWoriveRs 4 and the only tool needed is a solder- car Perfect f ’ a : ‘ : , : TRANSVISION, INC. © MEW ROCHELLE, WV" | jf raters, noboyina, tie 51k tow p ence 9 25 ; | ing iron. The kit comes complete with ht SIZES: Pi . . . No. 3... tubes, modules, printed circuit, speak- pu Transvision, Inc., New Rochelle, N. na RN-1 I No. 4... Ne: 8: | ee . : L; | Enclosed find $.. ; please send. «+ -Fran- | mrvatad boar | grip assures nay 3 26°: Finest | er, and Ivory colored plastic cabinet. vol sistorized VTVM- VOM kits | steel end. craftsmanship. A hard-to-beat value | ahiiinides nab iaieahiaiaie d.c. rom witzerland NG a. Fa Sa eAs eine Fen eeecenvenecsens ceeeaseenaen | nd [MONEY Back og extra, NEW COMPUTER TUBES : als WU vinta Wises conicucce sssencitpponsan pense | “SCOTT-MITCHELL HOUSE, INC. Sylvania Electric Products, Inc., is is pe ee oe ER Zone.....State........ | err. mzos, eit snonmwar, new vonn ia, w. v. | now offering five new electronic com- pol RADIO & TELEVISION NEWS Jar
January, 1737
puter tubes designed especially for the renewal market.
Four of the tubes, designated as the 5915A, 5964, 5965, and 6211, are miniatures. The 5915A is a miniature dual control heptode designed for computer applications involving long periods of operation under cut-off con- ditions. The 5964 is a miniature medi- um mu dual triode having a common cathode. The 5965 is a miniature twin triode designed for use in high-speed digital computers, each section fea- turing a high zero bias plate current, a sharp cut-off characteristic, and a separate cathode. The 6211 is a medi- um mu twin triode designed for fre- quency divider circuits in electronic computers and other “on-off” control applications involving long periods of operation under cut-off conditions.
The fifth tube, designated as the 6888, is an octal-based dual control pentode designed for long life and low failure rate in computers. It is used in pulse amplifier, core driver, and coincidence circuits.
ELECTRONIC SWITCH KIT
Heath Company of Benton Harbor, Mich., is now offering a completely redesigned version of its Model S-2 electronic switch.
The new kit unit allows simultane- ous oscilloscope observation of two input signals by producing both sig- nals, alternately, at its output. Four switching rates can be selected by
means of a panel switch. It provides gain for input signals and features frequency response of +1 db from 0 to 100,000 cps.
The circuit uses seven miniature tubes. Sync output is provided to control scope sweep. The instrument may also be used for observing input and output of amplifiers simultane- ously.
ELIMINATOR-VIBRATOR CHECKER
Electronic Measurements Corpora- tion, 625 Broadway, New York 12, N. Y., is now offering a combination battery eliminator and vibrator check- er as the Model 905-6A.
Designed especially for the auto ra- dio service technician, the new unit can supply 6 volts at 10 amps or 12 volts at 6 amps, continuously. The out- put voltage is variable from 0 to 8 volts or from 0 to 16 volts with smooth d.c. output voltage assured. It can also be used as a battery charger and is ideal for determining the starting points of vibrators.
January, 1957
100 N. Western Ave., Chicago 80, III.
due to inaccurate instruments
eHeck AND ADJus >
~ - Your Test Instruments with LABORATORY ACCURACY
Designed by MILTON S. KIVER Author of the Book
“Servicing and Calibrating Test Equipment’’ Published by Howard W. Sams & Co., Inc.
TEST EQUIPMENT
i 150i CALIBRATOR 2
Calibrates VOM, VFVM and other meters, signal, sweep and marker generators and oscilloscopes.
Voltage Accuracy +1% or Better
Avoid instrument errors that cause wrong decisions and time-killing rechecks in receiver testing. With the new, low-cost, laboratory-type
Model 750 Calibrator you can quickly, easily check test equipment accuracy and make necessary adjustments.
Provides standard of + 1% or
better in all of its voltage sections— enables you to calibrate your test instruments like the labs do, and give better service at lower cost.
a
iL “itl
ci 1
fh
Model 750 Calibrator
Complete with 5 mc crystal. Operates on 110-120 v., 60 c. ac. Sturdy metal case. Size: 8% in. high, 8 in. wide, 54% in. deep. Net wt. 6% Ibs.
*54%.
See Your Distributor or Send For Bulletin 750-N
Ba K MANUFACTURING
J
ore Top Pay Jobs in (a
Eg) SATV - ELECTRONICS -RADIO eS Bel
— High pay, opportunity, prestige, security ... all yours, as a qualified Electronics Technician! Get your training NOW in the big, recognized shops, Labs, and TV-Radio Studios at National Schools in Los Angeles, foremost since 1905. Here you work with latest Elec- tronics equip f i lly installed — finest, most complete facilities offered by any school. Expert, friendly instructors. Personal attention. Graduate Employment Service. Help in finding home near school. Part time job while you learn. Mail coupon NOW, TODAY... for full information.
NATIONAL SCHOOLS
J National Schools Dept. RXH-17 4000 So. Figueroa Los Angeles 37, Calif. § | Send Free Electronics Opportunity Book Today g
SAVE ON SURPLUS!
BC-906-D Frequency Meter— 144 to 225 me. Battery op- erated. Complete with case.
Only $695
TS-16/APN Test Set, Used for aligning and _ calibrating AN/ ARN-1, AN/APN-1 and altim- eter equipment. Has 28 volt vibrator power supply. | Audio Generator, other valuable parts. Com- $11 95 | plete with all cables and wood case..... Only . | Case Only for TS-16/APN—Sturdy reinforced $3 95 | wood, 1712"x111e"x15". Has many uses. .Only . j
FREE!
Send for our bulletins of hundreds of qual- ity surplus items.
All items shipped FOB our warehouse. On C.O.D.’s include 25% with order, Ohio residents add 3% sales tax. All items subject to prior sale.
I Name Age KOPELOVE ELECTRONICS CO. ee Dept. RN 157, 1919 East First St. Dayton 3, Ohio | ty State | ee eee 153
s * DEPT. M-295, 611 BROADWAY, NEW YORK i2, N.Y. Sewtth now olering tive new e1recrronic Cvuliie 3 . — S=— a a irre > hh
152 RADIO & TELEVISION NEWS ‘
HARVEY’s famous hi-fi consultants RECOMMEND
... the NEW
AUDAX KT
12 and 16 Inch TONE ARM KITS
Here is on altogether new —and superbly logi- cal — do-it-yourself development: professional- quality transcription pickup arms in kit form! You can assemble them in 10 to 20 minutes, with a small screwdriver or nail file as your only tool. Engineered by renowned audio pioneer _Maxi- milian Weil, the KT-12 and KT-16 kits are further refinements of an already famous and time-tested AUDAX design, now brought to the ultimate degree of simplicity and perfection. They pro- vide optimum performance with any cartridge ond represent a saving of nearly 50% over their factory-assembled versions.
KT-16 kit (16-inch)...
Same, factory-assembied -
KT-12 kit (12- inch) -
Same, factory
DYNAKIT
50-WATT ° Power Amplifier Kit This is the: amazing do-it-yourself package that audio perfectionists have been choosing for over @ year now in preference to more expensive amplifiers. Incorporating an ingeniously simple, unprecedentedly stable and utterly reliable cir- cuit by David Hafler (of “Uitra-Linear” fame), plus premium-quality components such as the superb Dynaco A-430 output transformer, the DYNAKIT delivers 50 watts at any audible fre- quency with incredibly low distortion—harmonic, intermodulation, square-wave, phase, pulse or any other kind. Listening quality is unsurpassed; construction time is around three or four hours thanks to the pre-wired printed $6975 circuit board; price is still only...
“the W/B STENTORIAN ‘DUPLEX’
“Super Concentric’ 12 Inch Extended-Range Speaker
A HARVEY Special!
Despite widely different
tastes in loudspeakers,
this beautifully made 12-inch coaxial unit has the virtually unanimous vote of critical high- fidelity enthusiasts as one of the smoothest and most natural-sounding transducers available. The huge magnet, the machined high-frequency horn, the extremely low-resonance bass cone, the carefully designed built-in crossover all con- tribute to the de luxe performance of the *Duplex,’ which even at its regular price is easily the equal of many more costly loud- speokers. At the present limited-offer price, it is a borgain without a rival.
Regularly $119.00 HARVEY speciat $7995
MAIL ORDERS SHIPPED SAME DAY AS RECEIVED
Include with your poyment a ‘generous for chorges — the excess will be promptly refunded.
HARVEY: ee
123 Avenue of - eeericas JU 2- 1500
Housed in a single sloping rugged metal case, this combination unit is available in either kit or factory wired
form. The battery. eliminator-charger can be purchased separately in either wired or kit form.
Write the manufacturer direct for full details on this and other instru-
| ments in the company’s complete line of equipment.
TRANSISTOR RADIO KIT
Philmore Manufacturing Co., Inc., 113-115 University Place, New York 3, N. Y., is offering a two-transistor “portable” receiver which is being sold in kit form at a very moderate price.
The circuit is of the t.r.f. reflex type which will drive a 4” loudspeaker. Two transistors and a germanium diode are powered by a single 9-volt “A” bat- tery. The tuning range is 550 to 2500 ke., which includes standard broadcast and some of the short-wave, police, and marine radio bands.
The whole circuit fits into a colorful
plastic cabinet which measures only | 74%"x5"x2%” over-all with retract-
&
able handle. The set weighs 1 pound, 6 ounces. An optional carrying case is available.
The kit comes complete with step- by-step wiring instructions.
SERVICE INSTRUMENTS
The Components Division of Radio Corporation of America, Camden, N. J., has developed two new instruments designed to simplify the servicing of radio and television receiving equip- ment.
The first unit is an r.f.-i.f.-v.f. mark- er adder (WR-70A) intended for use in sweep-frequency alignment of both black-and-white and color TV receiv- ers. It is designed to be used with conventional marker generators. It
provides a choice of four different marker shapes, permitting the use of the marker best suited to the response curve.
The second unit is an audio signal generator (WA-44B) for the hi-fi en- thusiast, industrial technician, service technician, and laboratory man. It features a wide frequency range from 11 eps to 100 ke. in four svages.
BERKELEY “FERRISTORS"
The Berkeley Division of Beckman Instruments, Inc., 2200 Wright Ave., Richmond 3, Cal., is now offering a new line of “Ferristors” which are designed to replace vacuum tubes in certain types of electronic equipment circuits.
These midget %,™” cubes perform virtually all vacuum-tube functions: input amplifier, gate, time base, deci- mal counting unit, coincidence ampli- fier, and control circuitry. They are immune to damage from shock, vibra- tion, and accidental overload and nei-
ther humidity nor temperature affect their performance.
The company is now making two classes of “Ferristors,” one for high- speed magnetic amplifier applications and a second type for counting cir- cuits. For full information on any of the units in the line, write to Depart- ment 1752 for a set of application notes. The data will be provided with- out charge.
RCA TRANSISTOR RADIOS
The Victor Radio and “Victrola” Division of RCA has introduced two new all-transistor pocket-sized radio receivers. These are the Models 8BT7 and 8BTS8.
Both models use four transistors and weigh approximately one pound each. The “Winsome” is available in either two-tone gray or turquoise and an- tique white. The “Stetson,” which in- cludes a plug-in for an earphone, is available in a choice of charcoal and antique white or pink and antique white.
These receivers incorporate the new- ly developed RCA speaker which is only 24%” in diameter and a little over a half-inch thick. It was developed especially for transistor receiver ap- plications. The “Winsome” will retail for $39.95 while the “Stetson” will be offered at $44.95. —30—
RADIO & TELEVISION NEWS
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January, 1957 153
T Ham Special! Famous BC-645 | [/,.. ...,7UST, ARRIVED! BC1206-C BEACON RECEIVER XMITTER-RECEIVER | | is24U=Si her! Beit 2 oa: Jee SPcatttea Gerken 32.
With DIAGRAM for all cables, N in ori
Easy Conversion ; to CITIZENS: BAND! EW. in- original packing te ps. BRAND, NEW cer wonterisl mobile Tz] ASB-5 RECEIVER FOR 420 Mc ey Brand New. less tubes. . $5.98
for 420-500 Mc. y As featured in “‘CQ’’ for October 1956. convert for phone or CW bs Easily converted, makes a marvelous USED, less tubes....., 2.95 way communication. CON- receiver pt 420 Mc band, with 4
VERSION DIAGRAM IN-| spit SCR-522 2-METER RIG!
You get it all, in original factory carton, La emplete wi cum @* -156
BRAND NEW, complete with 7 tubes, less power 1-95-M FIELD STRENGTH METER i's chammeta, Mechaearomed. Namal
" Kya 2 ala ey tude modulated voice. They’re going
PE-101C DYNAMOTOR for BO-645, has 12-24V Dine vasniieedatiiven. manatih input — to convert for 6V Battery | 95 ” ied ith all 18 tubes M
seecetion only = AN/ARR-2 ; oe pete :
UME ANTENNA’ ASSEMBLY, for BC-64o.. . .$2.48 Complete set of 10 Plugs 50 RECEIVER
COMBINATION Special s Receiver Only, with all tubes. . .$19.50
co Sonnon Bt BOX for above. ‘ - - $2. as Transmitter Only, with all tubes . $22.25
CONVERSION BOOKLET. i a ARC-5/T-23 TRANSMITTER
most useful surplus rigs oka. on : auton 2-832A, 2-1625 Tubes.
BRAND NEW SPECIAL PURPOSE TUBES $8.88 oe ee : : in Ori 1 Individual Packi a> te ‘ AR TRAN TT
JAN CRP-730A OMAGNETR ‘ON, Raytheon. Ba ; : ie, bee C-5 “TIARINE RECEIVER: = ANSMI new vita
- ~ : 9s
ype Comm. Transmitter 2.1-3 Mc BRAND NEW. with
tubes and Xtal $12.45
DYNAMIC HANDMIKE, with “Press-to-talk”’ ete NAVY RECEIVER TYPE ARB |
( CL s swell rig] OUR LOW PRICE E originally cost over $1000—yours for practically a ASB-5 INDICATOR Terrific buy! VHF Transmitter-receiver,
¥S-16/APN TEST SET. BRAND NEW, com- cord and plug—BRAND NEW, only. ------- = . so oie ot ate Brave weaDPwones, OC into ih | Soot 10° ei, Tol fa | arge earphone cushions, cor an eapued plug dee BENDIX DIRECTION FINDER BRAND NEW, special: 2 PBR ae rie MN-26-C. 12-tube te trol Navigation Di sditic : Y apt-a0-C. tes Be remote ene et Maw ones i 1500 SOUND POWER Headphone with $3. 95 Included. papetent Soe Overall: 8444" x Ke in 3 bands. 28 V. DC input, Ideal for commer- Dynamic Mike, BRAND NEW. 74/4" x 1514". 30_ Ibs. COMPLETE ‘WITH ALL Tusts, $21 50 °
ee
cial navigation on boats and planes. Complete installa. | tion comprises: 16.5 HI-Fl DYNAMIC HEADSET with Cushions a dim ai ek -C Receiver, used, with 12 tubes. Freq. Range: 40-14000 CPS. No a $5.95 a ds cxiet cuen cium tutes een tn eld
MOE patentee MICROPHONES —. ~ LORAN APN-4 MN26y BENDIX DIRECTION FINDER Excellent BRAND Cm ic. FINE QUALITY Carton teed laike ‘sas $79 NAVIGATIONAL
Carbon Throat Mike... 3 _ Seca like new, incl. tubes and dynamotor. "$18. 95 gg Mike i : > EQUIPMENT
Navy Type .....-.-- 2.45 1 1 Determine exact geographic position of your boat or NEW! Cathode Ray Tubes NEW: Bs yee AT Ae ee Ue plane! Complete, BRAND NEW installation consists eaaeaenapammeen of: ID-6B/APN-4 Indicator; R-9B/APN-4 Receiver; HEADPHONES PE-206 Inverter; Set of Ang Rabe $ 09.50 Operation manual; Brand New — et Description Used 129 29. High Impedance packed. COMPLETE Low Impedance . 1.99 . APN-9A LORAN Receiver Indicator, Easily converted for use sae yO ioe =. (featherwt.) ds SPECIA less tubes, NEW a is — — ili i see eeees = — TV Service €D-307A Cords, with PL5S plag (demilitarized) ‘BRAND NEW FR BRAND NEW SELSYNS | FE Operates from 5717/2 volts, 400 cycles. New tested.
Completely Assembled f pe Conversion diagram for 110 volts AC included, Supplied with 5” Scope | ' : BC-906 FREQ. —— bn . ‘ Any Type
4 elsyn Generator.
| METER—SPECIAL! 231G1 Selsyn Control Transformer. 1295,
‘ 231H1 Selsyn Differential Generator. oe + Cavity type, 145 to 235 CAPS FOR ABOVE
Mc. BRAND NEW in original factory packing, R24-ARC 5 NAVY TYPE BC-60S INTERPHONE AMPLIFIER. Easily converted soar y Shae oF yaaa (Simil if to BC-946) to intercom set—ideal for office, home or factory! Manual included. a re
BRAND NEW, with original schematic... ..$4.44 OUR LOW $8 BR BROADCAST RECEIVER PRICE ......0U08
DYNAMOTOR VALUES! ase T28K7, 12SHr. 1246. "13
For dynamotor operation, BC-221 FREQ. METER..............-$129.50
ily converted BC-221 FREQ. METER CASE a og ake % 19.95
; Se Complete with all 4 « sey SEA Alumi case for BC-221 or TS-164 Freq. Meters. BRAND NEW aw “ jo aed gy ig pupply using VR105. 2 ballast tubes, BC-457 TRANSMITTER—4-5.3 Mc. complete $7 gg ’ ? , ete. " nd BRAND NEW. 93, BRAND NEW, $399 Beet ane mitt reR—0.3 ° 7 Me. Complete with
Inside front: 540V .25A x 7s x 7%". In- (Add 50¢ for ait tubes "and. crys
side rear: 2” deep. packing) RAN’ . Shock-mounted Be. rs PRANSMITTER—7: 9.1 Me. complete with all DM-37 ¥ —~
oa aay oe Original Crystal for BC-221 $8.45 ova ge gaa 11.95 DM-40 14V 3.4A 1000 Ke BRAND NEW.............. BC-696 TRANSMITTERS to 4 Mc. BRAND ¢Q 9g
DM-53A 28V L.4A TG-5-B TELEGRAPH SET NEW complete with all tubes & crystal. DM-64A 12V 5.1A Made for USA Army Signal Corps. A dandy ae mes set SCR-274 COMMAND EQUIPMENT
a for 2-way communication. Sturdy metal conta PE-73C 28V 20A 44"xi") with hinged covers, Se een Att comeeEDeseription Excellent Orang
Used Use PE-86 = 28V 1.25A and headset. an ri 95 *-453 Receiver 190-550 KC...$9.95 $11. 95 $14.95 PE-103 6V sed, exc. id : 4 Receiver 3-6 Mc 7.19 8.29 11.95 12V 500V .1) ohare a 5
5 Receiver 6-9 Mc
. laa | C-456 1 PE-186 28V 11A BUBBLE SEXTANT | BC 450 S Receiver Control Box
BC-451 Transmitter Control Box
SPECIAL G.E. DYNAMOTOR Made for U.S. Armed Forces, | BC-696 Xmtr 3-4-Mc (like new) ... 5 8. INPUT: 28 V. D.C. @ 19 A. : : by AGFA ANSCO. Actually} pn BOT ee Eee OUTPUT: 1000 V. D.C. @ .350 A, | 95 y worth $150 or more! Has) 110 VOLT AC POWER SUPPLY KIT Model 5D48B9A. BRAND NEW.... ae a illuminated averaging disc
2 VOL f} for nighttime use Completel Cc. co an ams -t8 and a“? Reeoslvers “ ” = ° an be assembled ickly and easily, on - OLT BATTERY PACKAGE — with carrying case 9, 95) drilled chassis. Pinon tata the rear of be Sentind Y) 1—2V. 20 Amp. Hr. Wil- Only 274-N receiver and delivers 24 volts ze lard Storage Battery. $2.45 Lasae-cpeahnte es satis See eee Oe 2 ee Sees oe $7. of parts wi n metal case, instr tions. 1—2V. 7 prong Synchro- WRITE FOR FREE CATALOG! SPLINED TUNING KNOB for 27 74- N RECEIVERS. nous Plug-in Vibrator 1.49 | Picase include 25% Deposit with order—Salance c.0.D. Fits BC-453, BC-454 and others. 9c 1—Quart Bottle Electro- ctor ys ic bears $3.00. All shipments F.0.B8. Our Ware- cseeccenece lyte (for 2 cells)... 1.48 es
ALL BRAND NEW! BC- ANTENNA RELAY Combination Price. . . $4.99 & Radio Supply Co. Beets Value! Consists mE amp Willard 6-Volt Midget Storage Battery dicator, \O:10,. scale, Transm ter Re
Dept. N-1 jcator, Ap 0 scale, Srenemniveer-Be- & £ Amp. Hour. BRAND NEW. 3% x 1-18/10" = 2%. 51 Vesey St., New York 7, N. Y., CO 7-4605 case with ening relay eo OA ses Standard Electrolyte.....+.....-Only $2. Branch: 5009 N. Neva Ave., Chicago 31, Ill. BRAND NEW......--
January, 1957
STAN-BURN G PARKS
| CATHODE RAY TUBE SPECIALS |
ONE YEAR GUARANTEE | GE — | GE. Type a
aad |
etal etotatetetatdetat-tt ie adadaddadeaes =
y 2 25/1
SPPP PP SOLS PSS?
6.60... 48.2 *Aluminized—1NQUIRE FOR ANY TUBE TY
STAN-BURN CRT TUBES RCA LICENSED_MED. BY
PRICES SUBJECT TO CHANGE WITHOUT NOTICE
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consisting of: Porcelain sockets, coils, s formers, Pi eae condensers, ete. ONL $1.98 ies Si
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oe =| Technical
“PROCEEDINGS OF THE 1956 ELEC- TRONIC COMPONENTS SYMPO- SIUM" Published by Engineering Pub- lishers, GPO Box 1151, New York 1, N. Y. 240 pages. Price $5.00. Paper bound.
This volume constitutes the author- ized proceedings of the seventh nation- al meeting on electronic components and materials sponsored by the AIEE, IRE, RETMA, and WCEMA and en- dorsed by agencies of the Department of Defense and National Bureau of Standards.
Forty-three different papers cover a wide variety of subjects. In addition the book contains information on new types of components and data on the improvements that have been made on conventional components.
* * * “PROCEEDINGS OF THE CONFER- ENCE ON INSTRUMENTATION AND CONTROL IN THE PROCESS INDUS- TRIES" Published by the Armour Re- search Foundation of Illinois Institute of Technology, Chicago, Ill. 101 pages. Price $3.00. Paper bound.
This is a compilation of the papers presented at the Conference on Instru- mentation and Control in the Process Industries held in Chicago in January 1956. Twelve papers were presented, representing all phases of the field and a wide and varied segment of the in- dustry.
Those concerned with this special- ized field will find this volume inter- esting and informative and a spring- board to additional inquiry.
cd * *
“PHOTOCONDUCTIVITY CONFER- ENCE" edited by R. G. Breckenridge, B. R. Russell & E. E. Hahn. Published by John Wiley & Sons, Inc., New York. 640 pages. Price $13.50.
This volume is a compilation of the papers presented by 45 authorities at the Conference on Photoconductivity held late in 1954 at Atlantic City. Since the papers include basic theory, phe-
| nomenological theory, interpretation of
photoconduction phenomena, and re- cent data on the properties of impor- tant photoconducting materials, this book represents a definitive treatment of the entire subject.
Engineers in industry, government, and institutions of higher learning should find the availability of so much authoritative and useful data within a single set of covers a real boon.
* co oF “FREQUENCY MODULATION ENGI- NEERING" by Christopher E. Tibbs & G. G. Johnstone. Published by John Wiley & Sons, Inc., New York. 432
| pages. Price $8:50. “Second Edition.
RADIO & TELEVISION NEWS
Since it is only recently that the British Broadcasting Corporation has adopted FM broadcasting and set up the necessary equipment to handle this type of service, a training program had to be instituted to train the engineers who would be responsible for such transmissions.
This book, then, is one of the BBC training manuals which, although pre- pared especially for its own staff, is of interest and value to Stateside engi- neers. Chapters on the frequency mod- ulation of a carrier wave, interference and noise structure, interference sup- pression, FM propagation, antennas for FM, FM transmitters, limiters and dis- criminators, FM receivers, measure- ments on FM equipment, and practical uses of FM signals are included.
This new edition, which supersedes the volume originally published in 1947, is characterized by a more prac- tical approach than heretofore. A\l- though the treatment is somewhat mathematical and the equipment dis- cussed is of British origin, there is a wealth of data for all engineers within these covers.
* oe *
"ELECTRONIC TUBES, CIRCUITS, AND DEVICES" by Lewis G. Blevins. Published by Universal Scientific Com- pany, Inc., Vincennes, Ind. 620 pages. Price $4.50. Paper bound.
This volume is the last in a progres- sive series issued by this publisher and is intended for the slightly more ad- vanced student. The text covers elec- tron tube principles, and deals with electronic circuitry that employs tubes, industrial electronic controls, medium and v.h.f. radio transmission and re- ception, electronic computer circuitry, and electronic test instruments.
The inclusion of both schematics and pictorial diagrams makes it possible to use this volume as a home-study text as well as for the more formal courses of instruction. The various experi- ments outlined for the student can all be performed with standard, easily ob- tainable parts. The text is well illus- trated by photographs, schematics, graphs, pictorials, etc.
a * *
"BASIC RADIO & RADIO-RECEIVER SERVICING" by Paul B. Zbar & Sid Schildkraut. Published by McGraw- Hill Book Company, Inc., New York, for the RETMA. 105 pages. Price $2.00. Paper bound.
This is another of the laboratory manual series being issued by the RETMA in its current training pro- gram for upgrading radio and tele- vision service technicians.
Like the previous volume, “Basic Electricity,” this book is divided into “jobs” dealing with various sections of AM and FM receivers. The “objec- tives” are stated, the materials re- quired to perform the experiments are listed, and then the project is ex- plained. A test sheet on which the student can enter his results is in- cluded with each “job” section. As a laboratory manual designed to be used in conjunction with high school and
RADIO & TELEVISION NEWS
Increas
ations
January, 1957
Increased power output achieved through twin transistors gives 5 times greater usa- ble audio level than other receivers of this size using a subminiature output tube. 3 subminiature tubes of the latest multiple purpose type. One tube performs 2 func- tions, another performs 3 functions. Mod- ern printed circuitry for long trouble-free operation. Unaffected by vibration, Auto- matic volume control compensates for vari- ations in signal strength, holds volume as you set it. Permeability tuned I.F. trans- formers (iron core) are used to obtain best sensitivity, selectivity and frequency sta- bility. Latest type ferrous core antenna enclosed in case, Covers standard broadcast band—540 to 1600 KC. Size 2 1/32” h. x 7” w. x 421/32” d. Shpg. Wt. 4 Ibs,
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inctuded with each Crosiey Book Radio is a kit with which the owner can inscribe his Signature in 23 Karat Gold on the cover.
CROSLEY TRANSISTOR BOOK RADIO
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mart
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12 watt cap, 8 OHMS
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“MOST-OFTEN-NEEDED 1957 TELE- VISION SERVICING INFORMATION" edited by M. N. Beitman. Published by Supreme Publications, Highland Park, Til. 192 pages. Price $3.00. Paper bound.
This is volume TV-12 in this pub- lisher’s series of schematics and serv- ice data on 1957 model television re- ceivers released by some twenty manu- facturers.
As with the earlier manuals in the series this book provides over-all in- formation on each set, a schematic, a parts list, special service hints, in- stallation tips, voltage and waveform readings, and a photograph of the ehassis showing the location of perti- nent components, test points, and ad- justment controls. A chassis-number index is also included to facilitate lo- cating a specific set.
* * * “PROFITABLE RADIO TROUBLE- SHOOTING" by William Marcus & Alex Levy. Published by McGraw-Hill Book Company, Inc., New York. 326 pages. Price $5.95.
This book fills a gap in the literature which has not been adequately met since the U. S. Government’s book, “Establishing and Operating an Elec- trical Appliance and Radio Shop,” was released in 1946.
Subtitled “A Professional Guide to the Technical and Business Methods of Operating a Radio-TV Service Busi- ness,”’ this volume is for all those who plan to open, have just opened, or are struggling with a newly opened radio service shop.
The authors explain how to operate and organize a profitable venture and outline the techniques for handling trouble both on the bench and from the customers. The business end of the book is perhaps the most unusual and most valuable part since it outlines
‘how to get started, how to get busi-
ness, how to handle customers, estab- lishing charges, keeping records, etc. It is a valuable reference work for both newcomers and oldtimers who want to make more money. * * ak
“HANDBOOK OF BASIC CIRCUITS" by Matthew Mandl. Published by The Macmillan Company, New York. Un- paged. Price $7.50.
In this unique presentation, the au- thor has provided a schematic diagram, a description of circuit function, a dis- cussion as to the purpose of the cir- cuit, and information on the circuit’s characteristics and function on some 136 standard circuits frequently en- countered in electronic equipment, FM, AM, and TV receivers.
The material is presented alpha- betically and cross-indexed in an ex- panded master reference list at the back of the book. The user who is, for example, looking for a specific filter circuit can find it under several cate- gories depending on the application. In order to correlate the individual cir-
RADIO & TELEVISION NEWS
cuitry, a series of block diagrams has been provided in the appendix, cover- ing such pieces of equipment as black-and-white and color TV receiv- ers, FM receivers, black-and-white and color transmitters, AM and FM trans- mitters, etc.
* * *
“RADIO ELECTRONICS MADE SIM- PLE" by Martin Schwartz. Published by American Electronics Co., 1203 Bry- ant Ave., New York 59, N. Y. 184 pages. Price $1.95. Paper bound.
This compact manual is written for those who are interested in radio and electronics but have insufficient tech- nical background to understand the underlying principles involved.
Written in simple, non-technical lan- guage, the text covers d.c., a.c., vac- uum tubes, power supplies, oscillators, transmitters, detectors, superhet re- ceivers, and antennas. Three appen- dices include usual radio abbreviations, common radio symbols, and radio for- mulas. Mathematics is held to a mini- mum and diagrams and photographs are freely used to amplify the text material.
* * *
“SERVICING AND CALIBRATING TEST EQUIPMENT" by Milton S. Kiver. Published by Howard.W. Sams € Co., Inc., Indianapolis, Ind. 184 pages. Price $2.75. Paper bound.
This is a practical “how-to-do-it” manual for the technician whose bread-and-butter depends on his ability to troubleshoot and service equipment in a minimum amount of time and with maximum efficiency.
The text itself is divided into five chapters dealing with the pitfalls to avoid when using test equipment, sim- ple ways to check the accuracy of test equipment, keeping test-equipment op- erational records, preventive main- tenance measures, and servicing test gear. The author points out that often the technician is at fault rather than the equipment and explains the proper operation of various items of service test gear.
As is the case with all of this author’s books written for service tech- nicians, the material is thoroughly practical and is written in concise, yet easy-to-understand form.
* * * “INTRODUCTION TO PRINTED CIR- CUITS" by Robert L. Swiggett. Pub- lished by John F. Rider Publisher, Inc., New York. 98 pages. Price $2.70. Paper bound.
So wide has the interest in printed circuitry become in the past few years there was a real need for a reference work on the subject. While printed circuitry has been partially covered in general volumes, this compact hand- book deals with various manufacturing processes involved in producing these components, practical applications for such circuitry, and maintenance and servicing techniques for use with equipment incorporating printed cir- cuits.
The book is written for technicians, engineers, and industrial personnel—in
RADIO & TELEVISION NEWS
Send for FREE Catalog
In line with its policy of providing service and quality to its customers, Stanley Electronics of Passaic, N. J. has entered into an agreement with a crusher te crush and destroy any and all old or obsolete tubes to take them off the market.
For the first time: You can send all your old tubes to one location, Metallic Enterprises, Inc., 113% Mill St., Paterson, N. J. and receive credit dollars for them.
Our crusher wili take them all. We allow you a 5¢ credit toward each tube you buy.
Your order will include one or more of these famous brands
UNCONDITIONALLY GUARANTEED FOR ONE YEAR Broken Tubes — Smashed Tubes - Pretested Tubes Individually Boxed
Tubes in any condition Price | Tobe Price | Tobe Price are worth
f F
100 6AUSGT 6SH7GT 43 60 A 4 3
100
+3)
3AS_ 1.00 JA8GT 1.35 57
57
57 37 60
Pull them out of your attic. Dig them out of your garden. Crush them before shipping if ov want to. Regard- less of the shape its in, any tube is worth money. Any quantity —1 to a million.
pei we
eSskeshesssecsssssssas
S ° — b ° = »
HERE’S HOW IT WORKS... Suppose you send in 100 old, broken or
smashed tubes. You will receive 5¢ credit for each tube to be applied toward the pur- chase of 100 new tubes of any type you want. If your order is for less than the
tassystesssseess 83sssssctes sae
number you have shipped to the crusher,
~~ “
you will receive a credit for the balance to
be used against any future purchases. Pack and ship your tubes as scrap material
@® Westinghouse
post or freight prepaid to Metallic Enter- prises, Inc., 113 Mill St., Paterson, N. J. with @ packing slip listing the quantity of tubes
Busstesssssesy
117Z26G6T
shipped for credit. Send Stanley a duplicate of that slip with your order so that proper
credit can be given.— DO NOT SEND ANY TUBES TO STANLEY.
Brand New DU ‘0 AND
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30 TUBE SOCKETS 2¥2-lbs of HARDWARE 1S ROTARY SWITCHES 10 Electrolytic Condensers 40 Radio & TV KNOBS 40 BY-PASS Condensers 60 CARBON RESISTORS 60 MICA CONDENSERS 100 SET SCREWS
8 N22 XTAL DIODES 50 Ceramic Condensers
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50 RF CHOKES
20 POWER RESISTORS
1 Phono Motor 115 Vac.
50 TERMINAL STRIPS
200 f1. HOOK-UP WIRE
1 TRANS. 6.3V-110 Vac.
5 Meissner Plug-in COILS
5 PILOT PANEL LITES
50 FUSES 3AG UP
1 Meter Rectifier O-IMA.
1 IGN. COM 3V-15,000 VSEC.
‘25-Ft. Phono-Mike Cable 3 SELENIUM RECTIFIERS (65 MA. 110V.)
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* ms cs
“HANDBOOK OF SEMICONDUC. TOR ELECTRONICS" edited by Lloyd P. Hunter. Published by McGraw-Hill Book Company, Inc., New York. 832 pages. Price $12.00.
This volume is the work of thirteen specialists who have pooled their tal- ents to provide a complete manual covering the physics, technology, and circuit applications of transistors, di- odes, and photocells.
Most of the book is devoted to cir- cuit design and application data. In- formation is provided on low- and high- frequency amplifiers and switching circuits, direct-coupled amplifiers, transistor oscillators, and _ circuits using special semiconductor devices.
The book is self-contained and no
additional reference material is re- quired of the user. An extensive 68- page bibliography covering the bulk of the literature on the subject of semi- conductors is a valuable addition to this excellent volume.
* * *
“ELEMENTS OF RADIO" by Charles I. Hellman. Published by D. Van Nos- trand Company, Inc., Princeton, N. J. 343 pages. Price $4.95. Third Edition. This is a new edition of a well- known and popular basic manual for the beginner. It provides the essen- tials of radio and deals with radio communication on an over-all basis. There is a completely new chapter on transistors while the material on television and modern electronic appli- cations has been revised and brought up-to-date. The appendix, including tube tables, basing diagrams, and transistor characteristic charts, has been revised and enlarged. —30—
G-E 9” Portables (Continued from page 57)
a pair of germanium diodes as the ra- tio detector which drives the 10C8 audio stages. “B+” voltage originates
| from a single selenium rectifier supply
which delivers 135 volts.
The 9QP4 picture tube, recently de- veloped by the Tube Department of the General Electric Company, repre- sents a considerable departure from conventional picture tube manufactur- ing in that the tube bulb is blown into shape in the same manner as a light bulb. Elimination of the usual heavy face plate by use of this tech- nique results in a 9-inch tube with the remarkably low weight of two pounds.
A 70-degree electromagnetic deflec- tion system is employed, together with electrostatic focus. Since the glass used in the manufacture of this tube
w
A novel feature is qa convenient accom- modation for the a.c. fuse. It is located on one side of the chassis in a housing that resembles an if. can. This makes it readily accessible for examination as well as replacement.
a4
is not a perfect insulator, the high- voltage terminal appears on the base rather than on the bell of the tube. The value of this second anode supply is on the order of 8000 volts. Alumi- nization of the screen is not used be- cause no improvement in brightness would be gained with the compara- tively low anode voltage. A filter-type safety-glass is used, however, to im- prove the contrast ratio.
One photo illustrates the manner in which the wrap-on aluminum cab- inet is removed to expose the interior of the receiver. Servicing of compo- nents on the one printed board is rela- tively simple because all components are on one side of the board while the reverse side is exposed and accessible.
Operating controls on top of the cabinet are channel selector and fine tuning; contrast; vertical hold; and volume—“on-off.” Rear controls in- clude brightness, horizontal hold, height and vertical linearity. —30-
RADIO & TELEVISION NEWS
BUY THE WORLD’S FIRST COLOR TELEVISION ANNUAL!
136 PAGES COVERING EVERY PHASE OF COLOR TV:
coL.wlorRrR
comm TELEVISION
Selection-Operation+: Servicing
@ Color Sets On The Market Including:
A buyers guide
@ Picture Tubes to the latest sets and prices and Components and a complete Color TV Course
@ Technical Analysis complied by of Sets RADIO 6 TELEVISION NEWS
@ Servicing and Installing
@ Test Instruments for Color TV
@ Converters, Color Wheels, Vitascan
ZIFF-DAVIS PUBLISHING COMPANY—
Publishers of RADIO & TELEVISION NEWS, POPULAR ELECTRONICS, AND HI-FI ANNUAL & AUDIO HANDBOOK
January, 1957
GIGANTIC& MOVING"; /SALE
51 BIGGEST ‘4 BUYS!
“KIT KING” KITS EXCLUSIVE WITH LEKTRON!
ANY $i ITEM IN THIS AD FREE WITH ANY $10 ORDER!
SALE ENDS FEB. Ist!
LEKTRON’S FAMOUS <¢rcnc” DOLLAR BUYS!
) oe SuennaT yas MIKE, A. g sq.
clear a to
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1 Se jaws. TWIisT DRILL BLE ona BW rs. a Ba 70 a at thang ind boards. 15 types; 0 screw & 4 solderg a .. FUBULAR CONDENS.
e080
to 1000 Silver, : oy Wt. 1 Ib. Reg. $1
; 70 FN gage rater KNOBS. Ass lors, bakelite 2 Ibs. $1
3
col alesis. wt.
poo:
BMINIATURE 100 Ceramic CON- Fan 3. Asstd. ro ¢ 4 DENSERS! U.S.A. — circuits, condensers. $1 std. wes, mak Reg. $18 rg $i Four G-E iN69 DiI- ES. Leone go su- Pog to commercial. In poly sa" $2 SUN BATTERY & photo- cell. ta dia. tter than : “famed B2M! Reg. $1 $5.
10 “POLY” BOXES. As:
. too! TRANS! TOR ,2ou-
R 3. THnee TRANSISTORS— CBS printed circuit transistors; plug- $1 type. .
Rex. $1. 50 30 Bises. ‘standoff, but- ton mie Ce eet —. mrariety 5m: to 3 3. ECISION aes at values, “30, ‘onme t to ai 3 ye * s2i. We te «$4 4s ROTARY ousvenss. ceram lite ‘units incl. — ale ings. Wt. 3 Ibs. hee. gq 5S-PC. JEWELER'S Spaewanrene SET for miniat work. All differ- ent in “plastic case. Reg. $1 $2.50. 10 ee never. vyses. FP & st, rect. —_ sizes, Px “y S00me to
“45 ERIE TRIMMERS. ~|,8-5ommf. Reg. 85e $4
stov- ‘Wt. '3 Ibs. Ree-$4
MORE FOR YOUR DOLLAR!
2 TRANSISTOR LOOP- STICKS, tapped. Match transistors. Hi-Q ferrite adj. core; superior suincttene, broadcast band. Reg. $1.25 ea 10 TRANSISTOR SOCK- for sub-mini tubes, 3: Mica filled. Reg.
: 40 SUBMINIATURE RE- SISTORS in ih bes, 1%” long! 20 tee, ohms to 10 megs; $4 W. Reg. 85. 4 CRYSTAL propes. — ‘Noo — t ! nm poly Reg. $5. $1 OOP! Seen i! wi 000 ohm = lay; resistors, condensers, sockets. Wt. 2 Ibs. Reg. $1 $8.
3 HVY DUTY CHOKES.
200mils, we Strap
mtd. Reg. $2.5
3 our P er XFMRS. ose an ove re e) )
(Cho 50B5. a Roe. e each 50g a G-E PREAMP KIT for magnetic we TD Chassis, parts, diagram. Less 6SC7 (88c extra). wt. $1 1 Ib, Reg. $4.50. 175- ft. ~~ mes
RADIO & TELEVISION NEWS
Servicing Modules (Continued from page 62)
choice, therefore, would be the cutting of riser 3 or riser 7 between decks C and #. Let us assume that we cut riser 7. It would then be necessary to solder a new R, between risers 3 and 7, and a new R, between risers 7 and 10. These components should be soldered to the risers at the dip-soldered side of the etched board.
If C, were shorted, it would have to be removed from the circuit before a new C, could be added. Cutting riser 1 between decks A and C would also re- move C, and C, from the circuit. Cut- ting riser 12 between decks A and C would only eliminate C, and would, therefore, be the simplest way of mak- ing the repair.
A diagonal cutter should not be used to cut a riser wire between any two ceramic decks, since permanent dam- age to the module could easily result. This tool cuts by means of a pinching action. It is during this pinching ac- tion that the riser wires immediately above and below the cutters are pushed outward. Since the ceramic decks tend to oppose such movement of the riser wires, the decks above and below the cut wire could crack very easily. A very-fine-toothed saw blade
Ja
$9. 125 RESISTOR Saget CJ oe, Ms Ss 2w, a e-pe, eo tg KIT. values; to Br 7, C1 itt andl: 3/ /16, we swirenes. megs. 5a tool R “4 4 ’ . PA : re $1 716% steel socket 115VAC. | micro, push. 250 COIL FORMS. 15 in plastic case. Wt. — power types, w/ON-OFF ses $i Ib. 83 value. Switchplates. Wt. 2 Ibs. $1 Reg. $8.50.
[) Scres MAQNETIZED wdriver set. ideal
should be used for this purpose. A small power hand tool used with a thin abrasive disc (142” thick) could also be used for this. purpose.
Some critical circuit applications may require that a defective compo- nent be completely removed from the circuit by cutting the risers on each side of the component rather than only one side. An example of this might be a defective video-amplifier coupling capacitor. Disconnecting one side of the defective capacitor removes it from the immediate circuit, but stray capac- ity between the defective capacitor and other components may introduce slight video smear or other undesirable effects.
Although it is most convenient to solder the new components directly to the risers at the dip-soldered side of the etched wiring board, there may be cases where this is not possible with- out having to add components. This condition might occur whenever a de- fective component is connected to one or more risers which do not directly connect to the etched board. Under these conditions, it might be best to solder the replacement directly to the risers between proper decks, as de- scribed in the following procedure:
1. Refer to a diagram similar to Fig. 4 and decide between which decks and to which risers you are going to solder. Carefully remove the insulation from this section of the riser wires.
2. Loop pigtails of the replacement component around the scraped-off sec- tion of riser wires, and solder with a low-wattage iron. Pressure applied to
7 Psyc > LITES. Std.
Reg LUGS % RECEPTA- 15 AC/DC LINE CoRDS mber jewel, en- aa “Miniatur
2000 pes. CLES. Wide variety, in- springs, » ete, lor clocks, “ > . Ba $1 cluding fuse ts. . Wega $8. Cb . . _— 75 ‘Loo RADIO PARTS! - 1 lb, Reg. $3. Te. ‘CONDENS.
00025 : a 2500VDC. Reg. $2
ae TRANSISTOR Ata Me EXCLUSIVES
FOUR FEBRUARY SUPER BUYS! GIANT ONLY ONE DOLLAR EACH! SOLOS Ser teeY
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5 low, mtg. holes. $10 value!
TRANSISTOR TRANSFOMER BUY! | Saws Teanereres. Sev LOWEST PRICE IN U-S.! Silicon we P, hermetically sealed. (Un- MINI-METER SCOOP! Ch 5 steel In 10% e to mention mfrs a . 4 . Se
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*WRITE FOR NEW ’57 BONUS-BARGAIN BULLETIN!
NOTE OUR NEW ADDRESS WHEN ORDERING
Check items wanted. Return entire ad with check or MO. Inciude sufficient HOW To postage, excess returned. C.0.D. 25% ORDER down. Rated, net 30 days. Print name, address, amount money enclosed, in 131-133 Everett Ave., Chelsea 50, Mass.
pitied RTN-L —_- EXCLUSIVE PRODUCER OF "KIT KING" KITS
SENDING — AGE axcewinc-ZZ Nb FREE! COMIC AD CARD KIT
Lappe MARR Hy Senay eonypteg our complete fine of TV Service j
a “key”? man, arn send ai Phone Message Books, Job Tickets, Service
code, Commvunteate ithe cena ques | | Priciag Guide, File Systems, Service Contracts, Parts Warranties, P.0. Forms, Statement Books, Label Books, Sketch Pads, Cash } I 1 !
*roor’ ron St TH EE FOR
the globe. Learn at home quickly through famous Candler System. Used by best Books, etc. See them at your parts jobber. WRITE NOW! 4308 Milwaukee Ave. |
operators. Qualify for Amateur or Com- mercial License. Write for FREE BOOK. CANDLER SYSTEM CO.
Dept. 2A, Box 928, Denver 1, Colo., U.S.A. *At the most practical
LE A R N T Vv school in the west’
Work on late mode! sets—using modern equipment and service techniques: under qualified technician instructors Short resident and correspondence courses—no unnecessary math or theory—also UHF and Color TV. APPROVED FOR VETERANS... day and nite classes.
Write for free literature, Dept. 1A for residence—Dept. IAC for correspondence. id V.S.I. TELEVISI 4570 Firestone Blvd., Box 359 the riser wire during soldering shou fevbahitoles ON SCHOOL South Gate, California be directed in toward the center of the
162 RADIO & TELEVISION NEWS
| Oelrich Publications Chicago 41, lMinois 7
January, 1957 161
NEW INDOOR ANTENNA
Both UHF and VHF. Brings better reception than most outdoor antennas. Use on top of TV. List price $9.95.
Ky
Lots of 3
TUBE TESTER
Model 625K
@ Illuminated gear-driven “Speed Rollchart”
@ New lever-action switches for individual test- ing of every element
@ Tests all conventional and TV tubes
$49.95 wired 3 4’ Kit,
Brand New PICTURE TUBES
@ RCA Licensed @ One Year Unconditional Guarantee
Type
10BP4
12LP4
14BP4
16RP4
16LP4
Picture tubes shipped F.O.B. Harrison, N.J. Above types are most popular. However, you may order any equivalent size at the same price!
YOUR PRICE $3.99 each
TV TUBE BRIGHT- ENER
Fits all makes of picture tubes, AC parallel circuits. Completely auto-
matic. Easy to install. 89.
FREE POSTAGE in U.S.A. and Territories on orders over $5.00. 25¢ handling charge on orders under $5.00. 25% deposit required on C.O.D.'s. Please send approximate postage or freight on Canadian and foreign orders. Subject to prior sale.
ELECTRIC COMPANY 79 CLINTON PL. NEWARK.N. J.
Phone HUmboldt 4-9848
HIGH-PAY CAREERS
IN ELECTRONICS — TELEVISION — RADIO
Await Men with COMPLETE Training!
Nationally-recognized, accredited Central training is designed to get you into high-paying career positions in the shortest possible time. In addition, Central’s “Progressive Plan” is so arranged that each phase of training you complete qualifies you for a more im- portant, better-pay position. In just a few short weeks you are qualified for certain basic jobs. Then, with every additional training phase that you complete, you qualify “up the ladder” for more advanced types of positions. Central offers complete Electronics- TV-Radio training leading to an Associate of Science degree, and qualifying you as an Electronics Engineering Technician!
Thousands of Central graduates have been placed at almost every technical level in the electronics industry. Free nation-wide placement service.
3 PR OVE N TRAINING PLANS Don’t limit yourself! Ger the facts on Centrals complete
training that can take you just as far as you want to go in (Choose the one that fits your requirements) the electronics technician field. Send coupon today for FREE 1. HOME STUDY COURSE (with 9 kits of equipment)
99c each, single Lots of 3
brochure on your opportunities in Electronics. —Qualifies you for diploma, FCC license, and a variety of electronics jobs (or transfer into advanced resident training). 2. HOME STUDY-RESIDENT COURSE (with 9 kits of equipment )—Home study, followed by short period of resident training. Qualifies you for diploma, FCC license, and a wide variety of Electronics-TV-Radio positions (or continue with advanced resident training). An accredited technical institute curriculum.
3. FULL RESIDENT COURSE —Qualifies you for Asso- ciate of Science (A.S.) degree and top-pay employment opportunities as Electronics Engineering Technician. Part- time employment opportunities available for students while training. An accredited technical institute curriculum.
January, 1957
VETERANS! approved under Gl. Bil CENTRAL TECHNICAL INSTITUTE
Dept. W-17, 1644 Wyandotte St., Kansas City 8, Mo. |
Name Age
| Tell me more about how you can qualify me for a high-pay Electronics career. | |
| Address
City State
| 1 If Korean veteran, give approximate discharge date ;
63
cel your new
19570 MASTER
;module. This tends to press the riser | into the notches of the wafers adjacent 'to the point being heated and will maintain a good solder connection at these points.
Throughout all of the procedures outlined, care should be exercised to avoid damage to the module. If the protective coating should be inadver- tently broken where it protects a com- ponent, it should be repaired. A rubber base cement such as Pliabond could be
Fig. 4 clearly shows the service tech- nician what should or should not be attempted with regard to module re- pair.
As with anything new, it will un- doubtedly take a little time for the servicing field as a whole to become fully accustomed to modules. It is hoped that this material has started the service technician on a working knowledge of the use, replacement, and repair of modules used in TV and
(21st EDITION) used for this purpose. The diagram of radio receivers. —30/-
e What product best fills your needs? © What does it look like? © How does it compare? e Who makes it? © What does it cost?
Up-to-the-minute answers to all these questions are in The MASTER. Containing four to five times the product coverage of any other buying guide — there
How Safe Is Safety Glass?
Rudely awakened by the noise of a loud explosion in the middle of the night, Edwin J. Pfiffmer and the other members of his family went to the living room, only to find glass scattered all over it. The CRT in their TV receiver, which had of course, been turned off, had suddenly imploded. Although the safety glass in front of the CRT was covered with cracks, it performed its function in that it remained in one piece, as shown in the photo at the left. However, as the is no catalog like it. It is 350 right-hand picture shows, the force of the implosion blew it out of the front hea of the set and it landed on the floor about 5 ft. in front of the cabinet, per- factory-prepared catalogs in one ‘ mitting glass from the imploded picture tube to be scattered over a con- bound volume. ble distance. As occurs in some cabinet designs, the safety glass was not sufficiently well secured to the cabinet to provide the maximum protec- 15 4 6§ P A GES tion of which it is capable. On the other hand, it doubtless did much to re- ean tard flying particles. The incident is worth reflection by cabinet designers. the world’s largest electronic t= parts
catalog!
from parts distributors
SERVICEMEN, DEALERS! Buy, sell and bill direct from The MASTER. It shows list prices!
HAMS, EXPERIMENTERS! At your fingertips, those hard-to-get items found only in The MASTER.
HI-FI FANS! Pre-select components in your home. Hear them demon- strated at your dealer.
RESEARCH MEN! Specify, design more rapidly ...all the latest data in one bound volume.
1546 PAGES OF THE MOST CURRENT DATA ON: TUBES - TEST EQUIPMENT » CAPACITORS CONTROLS - TRANSFORMERS + RELAYS ANTENNAS + HI-Fl +» RECORDING & PA
WIRE & CABLE + RESISTORS +‘KITS, ETC.
© Over 125,000 items © Complete
descriptions © Specifications—Prices
© 11,250 illustrations © Fully indexed © 8), x11”, 6 ibs.
No matter what electronic component you look for
YOU FIND IT FASTER
IN THE MASTER Get the 1957 edition from local parts distributors — or write for list.
THE Radio-Electronic MASTER 60 Madison Avenue, Hempstead, N. Y.
RADIO & TELEVISION NEWS
V-M "KEY QUARTER" PROMOTION
V-M Corporation, 280 Park St., Ben- ton Harbor, Mich., has developed a co- ordinated merchandising program cov- ering the period to February 15th and promoting it as a highly profitable “Key Quarter” for retailers.
Keyed to the company’s national ad- vertising program in consumer maga- zines, the promotional package includes specially created window and in-store displays, outdoor advertising, tran- scribed radio spots, TV films, motion picture theater trailer films, newspaper ad mats, and full-color direct-mail lit- erature for use by dealers.
Dealers have been supplied with complete advertising schedules and all necessary advertising materials for lo- cal tie-ins plus detailed instructions on how to implement tliese materials.
Write the company for full details on the promotion and the products which will be emphasized during the promotion period.
* a * SELF-SERVICE DISPLAY
Walsco Electronics Corporation, 3602 Crenshaw Blvd., Los Angeles 16, Cal., has recently introduced a new self- service display which enables techni- cians to select instantly the required radio-TV alignment tool from among the 55 being offered by the firm.
The new unit eliminates buying er- |
rors by showing off the entire tool. Included in this complete alignment
and aeeney, tool section are items for |
1956-57 radio and color TV sets as well as three “Tel-A-Turn” tools with a built-in turn indicator,
For information on the display and the company’s line of tools, write to Bob Mueller, sales manager of the firm.
* * aa
NEW G-E TUBE CARTONS General Electric Company’s Tube Department has developed a new elec- tronic tube carton that is functionally
January, 1957
* nto’ TechRep is the world’s largest Field Service ceeenteniinn and because of this leadership can offer you— ® unlimited advancement ® opportunity to work any place in the world @ experience in the most advanced fields of electronics and
guided missiles @ personal security, real challenge, top salary and com- pensation for your skills
Do YOU Know
@ Philco electronic experts help prepare you for your TechRep Service career
e Philco’s especially written Home Study Course keeps you posted on latest electronic techniques, including radar, guided missiles and transistors
e Philco provides financial assistance to continue your education
Do YOU Know
. Philco not only will help you select the position in Electronics best suited to you but can and will provide you with periodic reports as to the openings in our world-wide organization for which you may be qualified.
“Get The FACTS About Your Future With Phileo:
Send Now to Dept. 21 for The Complete Story on What Makes The Philco TechRep Division —
“First Iu Employment Opportunities’
PHILCO TECHREP DIVISION
22nd & LEHIGH AVE., PHILADELPHIA 32, PA.
OIL CONDENSER SPECIAL
-5 MFD 7500 V. Sprague, rnc 4 49 SPECIAL PRICE. ’ “3% for $3.75
Compact 4 x 4 x 4(12) MFD 600V OIL Ben: 85c suitable for crossover networks, etc for $1. 59
SMAiL PIONEER SYNAMGTORS Ideal for Amateur or Commercial Service 5.5 to 6 eS Shere. oad hash filter & ttevass 14.95
DYNAMOTOR STARTING RELAY
coll. Solenoid type fully enclosed. Wi aw. handle 50 amps. Contacts = : 2a, 15 winding isolated from ground 2 "for $3.00
MARION 22" METER Basic o- pa mil has dual scale. 0-100 ma and 0-500 voc. mplete with S00" Volt _—— 3. 95
Multiplier
SPECIAL VOLTMETER BRAND NEW ROLLER SMITH 21/2” 18-36 VDC
REVODEX MICROMETER DIAL 1” Diameter dial, Satin Chrome plated. Grad. 0-100 div. sake Grad. 1-10. Actually counts 1000 div. or 10 . Contains mounting hardware aaa full instructions. * rotary 95 ductors, helipots, with 14” shaft. .
Filament Transformer Pri, 110V. 60 cy. Sec-
MB 1” Miniature Meter
0-1 mil. Scale calibrated ondary 6.3V @ 10 amps. in 20 divisions. .$3.95 | Good quality ....$1.65
TELEPHONE HANDSET ELEMENTS
Receiving and carbon microphone elements fits
eo. W.E. or Conn. Tel. handsets. 65¢ ea. or pr
G. E. RELAY CONTROL
(ideal for Modei Controls, Etc.) Contain 8,000 ohm, relay (trips at less than 2 MA), metal stri The sensitive je alone is wor than the 1. 1
low price ae RELAYS
Sealed Claire SPST. Norm, closed 3000 ohm coil, VY ea. 95¢
2 ma
Claire Telephone Type 11,300 ohm coil DPDT contac: mp i25V. Sens. 4MA. -ea. $3.95
Cutler Senden Contactor—1 ng 60 ey. pole sin-
le throw. Norm. open 25 a contacts .ea. $6.95
ermeticaily Sealed Relay” Coil 110V AC 6O cy
22°$9.25
SPDT Contacts 5 wanes ea. $1.8! 12 Voit DPDT OC Rela ea. $1.35 + ae Bh ai ow am AX 220V 6O cy. 45 sec.
ea. $6.95 = oe. Ps 3 ARE 5 prong 2000 ohm coil 7 FF ea.
i MFD 10,000
VDC 22.00 2 MFD 10,000
VDC 39.95 1 MFD 15,000
VDC 29.50 1 MFD 25,000
VDC 49.50 SMFD 330 AC
DC) -95
20 MFD 330 AC 2.50 8 MFD 660 AC
(2000 DC) 2.35
NEW PANEL METERS
G.E., WESTINGHOUSE, W.E., SIMPSON, etc.
600 VDC 1000 VDC
ext. Thermocouple 3.95 ERs 0-SO Microamp - - 0-S Amps DC.
BUD CE2008
vastiite Condenser. — hk we re eg.
9 Pin tube pin align Precision Meter Multiptier—1 Megohm
[0004 2500
-025 600 V
1 MF
Thordarson Fiona Transf. pri 11
cy. Secondary 24@V. 10 amps. 7500V Insul.
All merchandise sold on a 10 day money back guarantee basis
| Min, Order $3.00—25% with Order—F.0.8. New York
| PEAK |:
lELECTRONICS COMPANY! | 66 W. Broadway, New York 7, W. ¥., WO-2-5439 |
166
designed for maximum visibility, pro- tection, and ease of handling.
The carton slogan “Easy Open-Easy Out” emphasizes that the design al- lows miniature tubes to be quickly slipped out of the carton, thus solving a problem that has long plagued serv- ice dealers. Lustrous orange and gray colors are combined with a new shiny black type in modern styling to provide maximum impact and identification. Tube type designations are stamped in large letters and numbers.
The new carton can be opened with- out tearing the self-locking tuck-in flap
simply by exerting pressure at the fold of the tab. Then gentle pressure on the side panels allows a miniature tube to slip easily out of the protective inner cell.
Tubes are being packaged in the new cartons at the rate of 10,000 an hour at the company’s Owensboro, Ky. tube plant.
* ca oo JFD “SELL-A-BRATION"
JFD Manufacturing Co., Inc. has kicked off a massive distributor-dealer “Sell-A-Bration” to merchandise its line of “Colortennas.”
The promotion will enable a service dealer to earn merit points for each such antenna he sells. The bonus points can be earned any time between now and March 15th. Points will be redeem- able for over 900 premiums ranging from fishing rods to MG sports cars and trips abroad.
The campaign will be implemented by displays, streamers, newspaper mats, direct mail literature, novelties, and TV and radio commercials. Service dealers interested in getting in on the “Sell-A-Bration” are invited to write the manufacturer for full details and a
copy of the premium catalogue. * ca a
PICTURE TUBE CLEAN-UP
CBS-Hytron has introduced a “Gar- ry Moore Picture Tube Clean-Up Plan” which is being promoted over the CBS television network.
The program, designed to aid the in- dependent service dealer, consists of a demonstration by Garry Moore as to why the TV picture tube faceplate and protective glass needs cleaning. These glass surfaces, he demonstrates, accu- mulate enough smoke and dust in just a few months to cut down viewing en- joyment.
He then asks his viewers to “Pick up the phone and call an independent service dealer. If you do not have a favorite service-dealer, look under Ra-
MARINE RADIOMEN
READ THIS!
For 2 reasons: ist, we are preparing a new flyer chock-full of marine radio moneymakers for you. Send us your letterhead asking for one. 2nd, we have just made an ————— fortunate surplus pur- chase of come new Impedance Bridges designed not only to easure reactance and resistance of com- ponents, ‘but also to measure antenna resistance and reactance at marine frequencies. 4 Complete with a y box of plu standards and educational ee book wit special section devoted to arine antenna measure-
antennas to ge transmitters into the air.
. ate i TR e IN SURPLUS ! ! !
Extremely easy to make power supplies for both. Both come with schematics and instructions for the loth are super-sensi-
6 me, in excellent condition pc) all 10 tubes, mnel crystal oor. 420 MC: CPR-46ACJ, double enversion, 2 IF’s, Secheuean brand new TUBES!
HI-POWER LO-VOLTAGE ye ig value xfrmr. With 115 V. 60 cy, to taps 2, out comes 15.1 V. at 40 amperes! Move from 2 to 3, 4, etc. to 8, and output reduces to 14.3 V., 13.9 V. ete. down to 11.3 V. Series the secondaries of two units to get 30.2 to 22.6 V. Ideal with either selenium or silicon rectifier
Ibs. Cat. Big Bargain Catalog!
FREE! Send for your copy.
All shpts. FOB whse. Send 25 25% dep. with all COD orders. Item sub. to prior Ss d change of price without notice. Min. order
ARROW SALES. INC.
Western Mailin: paeoss Box 3007-R NORTH HO Ywoob, —. Central Mailing Address a Sales-Showroo 2441 S. MICH. A Dept. R., CHICAGO is. iLL. California’ Distributors’ Stores Inc., 1632 Venice, 7 ee 2005 Empire Ave., Burbank
G. L. Electronics, P.A.R.T.S., Inc.,
ALL NEW
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NEWARK’S Complete
ELECTRONICS
Catalog No. 65
EWARK
ELECTRIC COMPANY
Mail Order Division . . . Dept. R-1 223 W. Madison St., Chicago 6, Illinois
4736 W. Century Bivd., Inglewood, Calif.
RADIO & TELEVISION NEWS
dio & Television Service in the yellow pages of the telephone book. Then call the service-dealer and tell him you
want the Garry Moore Special Televi- sion Picture Tube Clean-up.”
Dealers have been mailed a broad- side to enable them to tie-in with the
promotion. * eo *
HANDY RESISTOR ASSORTMENTS
Clarostat Mfg. Co., Inc., Dover, N. H. has released a new power re- sistor assortment mounted on a handy wall card.
The “Greenohm” display includes six different selections of 2, 5, and 10 watt sizes and ranging from 5 to 50,000 ohms. The popular resistances selected for each card provide the technician with values best suited to his usual requirements. The resistance value of each resistor is marked on the card for ease in re-ordering or taking in- ventory. —30-
The 1956 Nobel Prize in Physics has been awarded to Drs. William Shockley, Walter H. Brattain, and John Bardeen (left to right) for their invention of the transistor. The three physicists are shown at Bell Telephone Laboratories in 1948, discussing the crystal structure of semi-conductive materials which form the heart of the transistor. It was through such purely theoretical studies and extensive laboratory investigations that the new phys- ical principle on which the transistor func- tions was discovered and explained. The invention of the transistor was announced by Bell Laboratories in 1948. Since that time the tiny transistor has evolved from a laboratory curiosity to a device that finds wide use in hearing aids, portable and mobile radios, new computing and control circuitry—until now its monthly sales run to about a million units.
January, 1957
SAMS BOOKS
keep you ahead in
ELECTRONICS
SAMS books cover every phase of Electronics for the service technician, engineer, student or experi- menter. Listed below are a few of the many valuable SAMS books available at electronic
parts distributors and leading book stores.
2 NEW SAMS BOOKS
“ELECTRONIC METAL LOCATORS”
by Harold S. Renne
Explains how Metal Locators operate, describes commercial types available, shows how to con- struct home-built units, describes applications. Fully analyzes the three basic types of Metal Locators: transmitter-receiver, beat-frequency and induction bridge. Includes chapter showing con- struction details for several different units, in- cluding transistorized types. Reveals the interest- ing applications of Metal Locators in industry. Special chapters are devoted to prospecting and mine detection applications. Includes valuable bibliography. 124 pages; 54 x 834”; illus-
trated. Order today, postpaid only $250
ELECTRONIC METAL
“SCATTER PROPAGATION Theory & Practice”
by Kamen & Doundoulakis
An invaluable book not only for engineers but for technicians who will play an important part in the installation, operation and maintenance of scatter propagation systems. Covers theory and charac- teristics of Scatter Peopeenens equipment used in ionospheric ; tropo- spheric propagation and aad ‘utilized; design and construction of parabolic antennas; the im- portance of Scatter Propagation for the electronic technician; discusses DEW Line and other northern radar and scatter lines. Written so you can understand it. 204 pages; 544 x84";
illustrated. Order today, postpaid only.. $3
SCATTER
SOR a USE THIS ORDER FORM te
LOCATORS..........$2.50
oO Color TV Training Manual. Prepares the Technician for ne TV service work. Covers principles of the Color TV system; Color receiver 2 chee installation and servicing sets. Includes color blocks out- lining the use of color test equipment. 260 pages; 814 x 11”; 300 illustrations. $6.95
TV Test Instruments. Revised and enlarged to ———- latest data on instruments used in Color TV servicing. Tells clearly how to operate each type of test instrument used in TV service work. 180 pages; $4 z= ii": illustrated $3.50
Key Checkpoi Prepared by the Howard W. Sams engineering staff. Provides many applications for general TV service work, including time-saving information on how to make quick tests at key bs ne to determine where trouble lies, and how to check overall performance of the receiver after repair, to insure gortent callbacks. 182 pages; 544 x oi strated $2.00
Servicing TV Sweep Systems.
operation, circuit function and — var- iations of verti and horizontal sweep systems common to most TV receivers. Tells how to analyze circuits; trouble-
shoots for you. 212 pages; 5%
illustrated
Radio Receiver Servicing. Covers the basic receiver types—gives time-saving hints for solving basic troubles, such as dead set, weak set, noisy set, etc. 192 pages; 5 % x 84”.. $2.50
TV Servicing Guide. Explains how to apply proper teenble-chanting procedures based on analysis of symptoms (most of which are illustrated by picture-tube screen
lhotos). Shows how to locate and elim- inate trouble in every section of the receiver. 132 pages, 8 ¥ $2.00
mail to Howard W.
(outside U.S.A. priced slightly higher)
Sams & Co., Ine, Dept. 1-A7 2201 East 46th St., Indianapolis 5, Indiana. for
Send books checked above. My (check) (money order)
PROPAGATION......$3.00
pe Recorders—How They Work. Explains pon theory, tape Me coneharintian, motorboard mechanisms, drive motors, amplifiers, magnetic heads, volume indi- cators, equalization circuits—covers everything you want to know about recorders. 176 pages; 544 x 844". $2.75
Servicing AGC Systems. Describes the oper- ation and circuit variations of the ee
plows & Calibrating Test wa Shows you how to keep your test instru- ments in reliable working order, how to determine proper oneraen and avoid erroneous indications. lains calibration procedures; gives ee | for performance record-keeping; shows simple ways to check instrument accuracy; describes proper maintenance and servicing of in- struments. 192 pages, 544 x 834”... $2.75
Se You Want to Be a Ham. Tells you what
=~ need to know about getting your icense and acquiring equipment. Covers
such subjects as: tye ney the Code; Getting Your Ticket; ing on the Air; Electronics as a Career; etc. 196 pages;
5% x 814"; illustrated $2.50 |
There is an authoritative Sams book on virtually any Electronic subject in which
Check be-
-oe HOWARD Ww. SAMS & ¢co., BOG... cceske :
Order from your Parts Jobber today,
Look
SAMS BOOKS on
the “Book Tree” at your
Parts Distributor
167
‘ONE DOLLAR ':
As much as $15 worth — Everything Brand tn: and sold to you with a money back guarantee.
3 = 20KV¥—500 mmfa H. V. . $1 100 — ASSORTED '/2 WATT. RESISTORS... coece "31 100 — FUSES 1 A + gee size 144" x Va" oes 4 ~ SETS SPEAKER PLUGS w 100 — ASSORTED WHITE TUBE CARTONS. .
. ANODE LEADS with 18” leads .
100’ — FINEST NYLON DIAL CORD 300 — SELF TAPPING SCREWS #8/32 x 56”....$1 - ASST. SCREWS, NUTS, NERS 85 RIVETS. 3
” RADIO KNOBS screw and push-on, SP panne standard size %” x 1%". SOCKETS octal and miniature 50 - ASST. MICA CONDENSERS some in 5%%...$1 50 - ASST. CERAMIC CONDENSERS a ey ASST. VOLUME CONTROLS less switch. - ASST. VOLUME CONTROLS with switen .... 30 - ASST. PILOT LIGHTS +44, 46, 47, 51. 10 — PILOT LIGHT SKTS. bayonet type, wired . 50 — ASST. TERMINAL STRIPS 1, 2, 3, 4 lug. 10 ~ ASST. RADIO ELECTRO. CONDENSERS. . "31 5 - ASST. TV ELECTROLYTIC CONDENSERS. ..$1 ) - 6 FT. ELEC. LINE CORDS with piug...... ‘$1 - TV CHEATER ——- with both plugs ......+$ 10 - ASST. WIREWOUND RES. 5, 10, 20 watts ..$1 2 HOOK-UP WIRE H SOLDER KIT.. -$ 000 LEAD-IN heavy duty.. SOCKETS with 18” leads. ° 10 - hee ANTENNA HANKS each 20 feet... +. -$1 25 - a. MICA TRIMMER CONDENSERS... .$1 ULAR CONDENSERS .1-200v.....-++s+- CONDENSERS .02-400v ...-- ese CONDENSERS
.001-600V.+see0++$1 CONDENSERS .01-600v CONDENSERS .25-600v ........
CONDENSERS -047-600v ....,. Ra
soeaeens .001-1000¥ ......$17
= TUBULAR CONDENSERS .01-1000v . $1 3— LF. MINIATURE TRANSFORMERS 456ke, 3 ELECTROLYTIC COND. 80/50 - 450v.......$1 CTROLYTIC COND. 40/10-450v,,......$1 34 noth be COND. 40/40 - 450v $
LYTIC COND. 50/30 - 150v,
= OVAL LOOP ANTENNAS ass’t. ni-gain types .$1 - LOOPSTICK ANT. new ferrite, adjustable... .$1 12- RADIO OSCILLATOR COILS 456kc ......$1 3-2 MEG rae CONTROLS with switch ..$1 1 = BEST 4” PM SPK. 1.47 oz. alnico +5 magnet . .$1 1— 5” PM SPEAKER ainico #5 magnet oee$l 2 = $2.50 SAPPHIRE NEEDLES 4000 piayines ...$1 2 — SELENIUM RECTIFIERS 1-65ma. 1-100ma....$1 5- aren CRYSTALS 2-1N21, 2-1N23, 1-ING4 .. °3$1
25 — 470 OHM 2 WATT RESIS 10% 31 25 - 100K OHM 2 WATT RE! SISTORS 10%. --$1 3 - AUDIO OUTPUT TRANSFORMERS sore type 3 3- gs 4 At TRANS. 6k6 or 6V6 type, 1 = SET TV KNOBS standard type, inci. escutcheon| 3 T- $3 CRT BOOSTER new life to old tubes 1 = TUNER TAKE-OFF COIL #+XM-752 1 — LATEST GOLD GRILL CLOTH 12” x 18”. : - LB SPOOL ROSIN CORE SOLDER 40/00 .
~ SPIN TIGHT SOCKET SET 3/16” to 7/16”... $< TV ALIGNMENT TOOLS 7”, 12”, 18”
ON SMALL ORDERS—Please inciude stam yp postage, excess will 4 refunded. Larger orders will be shipped express collect.
CAPITAL ELECTRONICS
218 FULTON ST., N. Y. 7, N. Y. CO-7-7842
BOX CHASSIS
L M B OFFERS FREE
inside LMB boxes
10 tested kit diagram projects for the builder. Each one of these kit diagrams built by a recognized expert. Kit projects are complete in every detail. Circuit dia- gram, photo of project both front and rear photo. Rear photo shows wiring and parts. Detailed instructions for building, complete parts list and approximate cost. Complete to build except perts and your distributor can supply the »arts. Ask your distributor for the list of LMB kit Diagram Projects. If he them, write to
LMB
168
does not have
1011 Venice Bivd. Los Angeles, 15, Calif.
Within the Industry (Continued from page 32)
ucts Co., Inc. has promoted J. R. JOHN- SON to the post of vice-president in charge of sales and merchandising .. . DR. JAMES F. BATTEY is the new gener- al manager of Clevite Transistor Prod- ucts of Waltham, Mass. ... MARSHALL P. WILDER has joined Allen B. Du Mont Laboratories, Inc. as staff engineer in charge of the company’s storage tube development program ... The Audio Division of Ampex Corporation has named C. D. DuBOIS national sales manager .. . DANIEL J. TELL has been appointed sales promotion manager of the television-radio division of West- inghouse Electric Corporation. He will make his headquarters in Metuchen, N. J.... The appointment of RICHARD M. KLEIN to the newly created post of product engineering manager of the electronic product sales department has been announced by Sylvania Elec- tric Products, Inc... . DAVID C. ADKINS has been named public relations man- ager of CBS-Hytron of Danvers, Mass. . . . DR. RAYMOND H. DuHAMEL, re- search assistant professor and super- visor of the Antenna laboratory at the University of Illinois has been named head of the research and development antenna group at Collins Radio Com- pany, Cedar Rapids, Iowa . . . ROBERT S$. BELL, executive vice-president and general manager of Packard Bell Electronics Corporation has been elect- ed president by the board of directors
. SAMUEL OLCHAK has rejoined De- Wald Radio Mfg. Corp. as general sales manager .. . The appointment of L. §. PRESTON to the post of chief engineer has been announced by Electronic En- gineering Company of California .. . CECIL R. RUSSELL has been named vice- president of the J. B. Rea Company, Inc., Santa Monica electronic computer
firm. ” *” ok
PETER G. BUTTACAVOLI has been pro- moted to the post of national service manager for the re- ceiver division of Allen B. Du Mont Laboratories, Inc.
Formerly man- ager of the com- pany’s field techni- cal services, Mr. Buttacavoli is well known for his lec- tures on television receiver servicing for both black-and-white and color TV sets. He has also served as technical supervisor and field service representa- tive.
In his new post he replaces Joseph Hatchwell who has been named head of the company’s new government di- vision field service department.
a oo * RADIO CORPORATION OF AMERICA has honored five service organizations named winners in the company’s na- tional competition for achievement of TV customer satisfaction.
poe
ete “Columbia
MATCHED PANEL METERS Brand New boxed. Fac Fresh. Guaranteed ~ one year. ‘Available “i either Round or Square Two Inch Si:
D.C. Volts
D.C, Milliamps A.C, Volts A.C. Amperes
A.C, Milliamps $1 ‘85 «.
ALL nance IN STOCK. uick action!
RICED FROM needs. ARR-5 RECEIVER
27-143 MC. AM or FM, fa condition
aa Uvoqpeney = Shift Receiver str 47) ’ Will work with any teletype equipment, Excetient
condition $32.50 Local Hi-Fi Fi Manufacturer Goes Bust!
our gain! LOOKIT THESE BUYS! ”
D.C, Amperes
Write us
. Or
A_ COLUMBIA AM-FM TUNING Was used i
e: Stock up NOW! Each. METER NRECTIFIER: Each CORD: UL
5.3-7 MC. XMTR. BC-456 MODULATOR: Exce: — Lomeli coger Be de,
New, low price TRIPLE. RECEIVER | RACK With shock
DOUBLE XMTR. RACK. With shock mount ALL popes For SCR-274N or ARC-5
- Onl FLEX CABLE TACH Shia aie —— ore tS) ca All orders Angeles posit required. ‘A , Ag) subj to aie pM “hints mum ORDER OPEN FRIDAY NITE TILL 10 P.M.
ELECTRONICS
ONTIATAVME 2251 W. WASHINGTON BLVD. LOS ANGELES 18, CALIFORNIA
NEW—TRANSISTORIZED
RADIO ams \\
Model TK-104, a professionally engi- neered, completely transistorized super- het receiver kit. @ Printed Circuit Chassis 4 transistors ® Self Contained Speaker—18 mw. Out- put External Phone Jack High Gain Ferrite Loopstick Antenna
Completely Sub-miniature
Measures Only 6 x 4 x 2”
Complete Easy To Follow Instructions Model TK-201, a two transistor preamp- lifier kit on a printed circuit board. Complete with all parts and simple easy
& % ®@ Texon Leather Case & * *
to follow instructions. The wide fre- quency range of this preamplifier will please even the most discriminate avu- diophile.
Order from your dealer or jobber or for more information write today to:
TRAN-KIT ELECTRONICS
467 SOUTH Sth AVE., DEPT C3) ar VERNON, N. Y
RADIO & TELEVISION NEWS
The “President’s Cup,” presented by Frank M. Folsom, RCA president, was presented to Louis E. Randle, president of Associated Distributors, Inc. of In- dianapolis, Ind.; and to the RCA Serv- ice Company branches in Dallas, Tex.; Fort Wayne, Ind.; Chattanooga, Tenn.; and South Portland, Me. Branch man- agers W. R. Seuren, R. C. Bryson, R. P. Malone, and H. G. Minnick accepted the awards for their branches.
The awards were made on the basis of speed and efficiency in handling cus- : tomers’ calls and in training service é Eee - o. r. side technicians for RCA Victor dealers. x < . § . tts a ia aaa
es ‘ 4 ‘ bel Sfystel,* ad illuminated “dual scaté <S-meter.>..S-
“meter fimetions withAVC off. =:Hag=Tive z. Se ae selectivity from 5009000 cycles-and precision PHOTO CREDITS ca “aexs ia By ge ea RTA ee : Boe Plus voltage. regulator and rectifier; Pensitivetie Page Credit ; 2 Cie) MY was on alt Bands. Sizes: 20"10¥2""x18
87.International Business Machines Corp. 5 nase Speaker, wt. {ii is i $B, Cruft Lab., Harvard University -
39 (top), 96, 167..Bell Telephone Labs. You NEED: PAY. or ONLY’ 33. 508 ‘DOWN: casa PRICE 1s $395 oa: 89 (bottom). .University of Pennsylvania : 4 Write for Our Complete List of Hallicratter Model:
40 (top left pictures) The Bettman Remington-Rand oe wed A < <> AT THE ; ‘,
WORLD'S TARGEST DISTRIBUTOR OF AMATEUR | RADIO. EQUIPMENT — PAY ONLY 10% DOWN!:
57, General Electric Co. Get the Story on the = d
GO... 0% Emerson Radio & Phonograph Co. ; Paes i Bp, ts GLOBE KING 5008: .$38:10 PER Moe National Co., Inc. Bee — & Fe “GLOBE* CHAMPION 300: $24. 47. “PER: MO.: Sperry Gyroscope Co. " ; “ . y = GLOBE SCOUT 658: $745-PER MO. . White House Signal Agency - : % “GLOBE CHIEF 90: KIT: $5.00 PER. MO. Perkin-Elmer Corp. can *SCREEN MODULATOR KIT; $13:95°. Sebeesecedceces.s iwle J: FORser *TRANSISTOR CODE OSCILLATOR: P- 95 6 METER: CONVERTER: $24.95 “SWR: BRIDGE: $16.95 - ; *CONELRAD KIT: $22.50
Aine”
Per Month
Py Tg? > 7s
KK
‘ 4 fe me py wae
aa: é
7 Ym
Admiral Corp.
aay } edt PN tes) IRS $M) Pail iy
Sylvania Electric Products Inc. Tung-Sol Electric Inc.
eel ee nts © ON
ERRATA
In the article “Realistic High Fidelity—
Horn L and E.
51 of our November 1956 issue,
“Hypex” was improperly used.
is an arbitrary and coined expression de- sed for use as a trademark, and is used
currently for the p.a. speakers made only by
Jensen Manufacturing Co. These horn speak-
ers generally employ hyperbolic-exponential
flares, which facilitate design features such
as increased throat resistance near cut-off a
and reactance annulling of speaker stiff- Pri.
arn yf eet Lat
“with printed circuit
PAM Sy
4 ee
ness by horn mass reactance. The Jensen lease Send Me: [] Free Catalog ...(] Hallicrafter Information
trade: k “Hypex” should only have bee used "with seiovenes “te species made by » To 3 bie WR phone poy - ++ and your
this company and not as a descriptive designation.
In the article “Bandpass and Rejection Filters” on page 149 of the above issue, a d-return resistor has been omitted from i : : ADDRESS: . ON A a ey Fc mapa —_—,- : - ines oa ‘ a etween p ° gp and ground. ° a
341
In the article “New Transformer Design for Power Amplifiers’ on page 74 of the a eS eee above issue, the value of the current feed- ; back resistor in Fig. 6 should be .33 chm | | REVOLUTIONARY TEST CONNECTOR | GET T INTO
rather than 33 ohms. The decimal point was } ‘ Ask your Jobber for E-Z Hook Test removed due to imperfect printing. Probes. Avessingty Ganaké. . ELECTRONICS oe fully insulated . . . patented Hook
In the article “New Emerson Color Receiv- are a - « + nothing “7 ohn ers’ which appeared on page 68 of the oekens Deere aaa er November 1956 issue, the convergence mag- } Sheer cpwcatladt ovtdghe’ Sci- nets are incorrectly labeled in Fig. 2. The entifically designed for better, magnet identified as the blue convergence : ~ ; safer connections, It’s terrific. Get magnet should be ‘red; and the one identi- 47 one today. B-& Hook Test Frod- fied as the green con woo 73 a, Sewer Woodburn, Coving-
verg ton, Ky.
should be blue. Posts, o
The following component should be added aii P to the parts list shown on page 55 of the TAPE RECORDERS Valparaiso Tech trains for top flight positions. November 1956 issue (“A Volume Expander + siaticuaae aioe enaitem rane, for Hi-Fi’): Cie—.022 ufid., 400 v. capacitor. Tapes—Accessories automation. color television. mats and earaness
theory and laboratory. Major companies visit
iis as Nationally Advertised Brands MERITAPE echeck for our graduates. 21 months’ course.
Pg reference to the article “Designs of UNUSUAL VALUES Low Cost, High High school grad. or equivalent. Dormitories
‘uture,”’ pearing on e@ 47 of our Send campus, Start Jan., April, July, Sept. G. I. November 1956 Coan ae m sketches Sor Buse Catsneg neg Re- approved. Write for catalog.
were the work of Harley Earl of Center Line, DRESSNER in boxes or VALPARAISO TECHNICAL INSTITUTE
pap on Boe — } ag been so credited. Frosting teeny. cans. Dept. RD Valparaiso, Indiana
January, 1957
WRITE FOR BONUS CATALOG
New, Unused @ Individually Boxed
T U KR 7 Ss FULL RETMA
WARRANTY
No Electrical or Mochentoat Relects
z4 -45 6AVS -80 45 1 35 1AX2 .95 GAV6 45 Ss 45.1 eae -50 183 .65 6AX4 -BO0 6SA7 50 12866 .6 IRS .50| 6GAXS -75 6837 -65 12BH7 .65 174 = .50 6 BAG 45 6SK7 50 12BY7 .97 ius .45 | 68Ccs 60 6SL7 -55 128A? .64 1X2 = .85 | 6BEG 45 6SN7 -55.12SK7_ .4 3v4 Cis? G 1.15 6SQ7 -55.12SN7 .5 SU4 .45 6BK7A 1.11 6T4 1.15 128Q7 .5¢ sv4 lw 90 6T8 75 258Qq6 .& SY3 .65 GBNG 1.19 6V6 55 2516 43 GAC7 .65 6806 90 6w4 35 25w4 4 GAGS .45 GBQ7A 1.30 6x4 -40 35L6 6 6AKS .6¢ 4 3= 6X5 45 35w4 S 6ALS. .4 50 8 88 35Z5 4 6AQS .45 6CD6 1.08 12AT6 .40 SOBS an GAT6 .40 GCF6 1.25 12AT7? .65 SOCS 5S 6AU4 .95 6C 1.65 12AU6 .41 SOL6 5 6AUS .60 6J5 40 12AU7 .50 7 8 GAUG .45 6J6 45.12AX4 .68 83V 1.2 FAMOUS BRAND PHONO CARTRIDGES
Original Boxed, Money Back Gtd.
RPXOSOA .001 & .003 (SS)....... 6. RPXOS2A Golden Treasure (DS)... .$19.25 RPXOS3A Golden Treasure (DD). . .$28.00
Repl # Need! “TETRAD** Diamondt
Rpsois or RPJO3S Single (S mo or 78 Single (D) *‘TE
nese makers quality tape. Precision
pat
Splice Free. Fre 3 fot IPS 40-15KC Oxide Wnd In.
SINGLY @ $1.5
Pp 01 A Dual (DS) .001 & .003 Sy id 2038. 98 } 450 3A Dual ( = ett
PJOLD or RPJO Single ag a
PJOO3 or RPJOO4 Single “D) **TETRAD”. ‘TRAD"’t
FINEST HI-Fi RECORDING rare 1200 Ft.—7” Reel ots Money Back Gtd. $1 45 of 12
ed & Slit, Gtd. ren output.
$1.50 EACH;
NEW IMPROVED ‘'TAB" Hi-Fi SPEAKERS
With a ¥~ Network Ticonal Ainico S Pius to 8 Ohms V.C.
ge
max, 2s Watt /20-20,000 Cycles. WODEL PASHAK .. wee eereueees $27.50 12” TRIAX, 20 Watt/40-20,000 Cycles. MODEL eget peerytic: $28.50 12” COAX, 20 Watt/35-18,000 Cycies. MODEL F12H2x
$2
Pho
inel pee transformer
C’RAY TUBE SB8P1 $1.49; with socke . DIEHL ogy vo PM motor 10,000 RPM, 12 to 28 VE CRYSTAL piopes IN23B @ 69¢; 10/$5; IN21 @ 6 $1 VOLTMETER AN Type 212” D’Arsonval 0-30 VDC. eae st @ $3 r S
SPECIAL @ IMA New Miniature Sq. sonval Myvt., better 2% accy, Speci
"TAB" SPECIALS!
MILLEN 156” Chrome Knob, 180° CW 210007. Reg.
SPECIAL 39¢ @,3 for $1 secd
TRanSronmen, 115 VAC/Pri, 24 volts @ 8
6.3V & 18V or 24V, wget 5 e.
sreciat ss. ]wccvcvecscsseveresscses ‘ior $9
MBO DC Power Parts Package 18 VDC
& F. W. fier,
OD WOR. 3 so no 0 os one chs seseesas SPECIAL $11 t $2
DC. Meg, B20... -20 005 vse oesscce TAB” $1.85
4A_ Precision 50,000 ohm Pot, reg. " $6,
-R.
“TAB” @ BE... wcrc sr reeeessenesees 3 for $9
Electrometer CKS697/S70AX, mini tube, bs ior
Da» bce. 046d 62005 ot Saas Oke eee wee $10 IMA DE JUR 3” Rod Bkite Csd 2310 wae TAS” Be. pec scope soccer sessecsnes teas lor $10 SOOMA DE JUR 3” Rnd Bkite Csd ¥3i0" meter, SOUR” @ BS. . wncccessevccescccvssees ¢ $5 Eeeoteie Pen, Precision Oiler or Carbon Tet, “SPE. CIAL OS on wc bode ceorsveocscpeesesesiss 6 for $S NEW PHOTOFLASH S2S5mfd/ oon aa me ose "ds, gtd low leakage, famous mfgr, 23; lass, 5 gros éneen 36 a 63s 6506 “TAB” 2 "3: 2/si2is pms
3PDT ey vy 10 amp 14
hone-CWw- -Filter, Cord, Plug & Jack 1020 cy ‘iter,
A 3 PERE gar pee “TAB’’ @ $1.98
AC & Battery Inbuilt All in One Comera Case Uses new lo <4 fe ~~ super
40V Batteries SOLD WITH “‘TAB’’ MONEY BACK
Hi-
See Selected, GTD ist class image Siena viewing tube
patie mite screen.
INFRARED SNOOPERSCOPE le Dark Tube
Tested for resolution,
sensitivity, simplified design 2” dia. i Resolution, Tube & BEctaccceren Special @ $4.75; 2/$9
KITS!
KITS
All Kits Contain Most Popular Values & Sizes
EXTRA: ONE FREE KIT WITH . EACH $10 KIT ORDER. Precision Resistors 25 Power Resistors rtd Switches 6S Mica Cond's s parvon Resistors® 280 ft Mookue wi i 5 uw 36 Pane! Lamps 100 Fu “4 si 10 Electrolytic Cond’s 35 Ceramic Cond 15 Volume Controls 10 Rotary Switches 25 Tube Sockets 6 Crystalis 50 Tubular Cond’s 60 Inductors & Coils 500 Lugs Eyelets® 5s saierenwieenes 10 Bathtub Oi! Cond’s 10 —_ Lamps 5S ibs. Surprise Kit 40 Insulators 10 Xmit Mica Cond’s * In Plastic Box $9 a er re only ¢
66 99 of muse only) SS in’ oraer TAB? = p= via R-Exp 3.” Prices
ject ih ls Dept. 1RN7, 111 LIBERTY ors *.° e. PHONE RECTOR 2-6245—CAGLE
¥. ¥. NirA@PARTS™™
170
wre
JANUARY
While every precaution is taken to insure accuracy, we cannot guarantee against
the possibility of an occasional change or
issi in the preparation of this =I
ADVERTISER PAGE PN ENED aa toee svnctw cdecd senses 158 Alexander Hamilton Institute............. it Allied Radio Corp. ............ 9, 96, 101,
105, 106, 107, 108, 109, 110, tf, 120, 151 American Technical Society.............. 102 American Television & Radio Co. ........ 130 Amperex Electronics Corp. .............. 144 EE FI Ga ig big in hedecesdocsces 114 I Bs SDs kc Fae edad Se yon bees oe 147 OU Bs FOG. asc he ob Fe Wo vresccoccns 166 Ashe Radio Company, Walter............. 121 i ND esos ns wb ucesaccdans 120 B. & K. Manufacturing Co. ...... 75, 119, 153 Baltimore Technical Institute............. 132 Barry Electronics Corp. ................. 171 Beckman Instruments, Inc. ........... ...104 Bell Telephone Laboratories.............. 18 NE a cs eke ius one Ca bcae hbase 100 Bionder-Tongue Laboratories, Inc. ........ 99 British Industries Corp. ................. 145 Burstein-Applebee Co. ............000000- 136 NOD: Aceny ¥ oe Fapssrsrevevinesveecs 21 SOD UNG MOD, oo sidv inns 050 deb cc ceces 181 PT TA eee 168 Capito! Radio Engineering Institute........ 29 Se ORNOD - Go carp chase. we cc0c nes 171 Central Technical Institute............... 161 Century Electronics Co., Imc. ............ 102 Champion DeArment Tool Co. ............ 112 Channel Master Corp. ................05. 15 Cleveland Institute of Radio Electronics .32, 33 Columbia Electronics ..............+.005: 168 PON ns wchodctiiecsieotieceats as Coyne Electrical School............. 100, 127 DeJur Amsco Corporation................. 78 DTD . recceeteentdulbecctabhiess> 14 DeVry Technical Institute.............. 5, 13 DE 6 obnt'00c cgmerdpetinsseedssvecdss 169 Duotone Company, The.................-- 140 Se PN 265 6 5.5 on en eadewhe coeevats 142 Dynamic Electronics-New York, Inc. ...... 98 E-Z Hook Test Products.................. 169 Editors & Engineers, Ltd. ................ 94 Electronic Chemical Corp. ............... 141 Electronic Instrument Co., Inc. (EICO).35, 36 Electronic Malin Co. ... 22... 2c ccceecevess 145 Electro-Sonic Laboratories, Inc. .......... 150 SEN 5.53.40 6d dkbab ed veces udon 8, 17 eM Rts pAaee bee dan ebenecntiess 137 Cet SS 5 ces cedennenctacteesed 131 Fairchild Recording Equipment Company.. .139 Fisher Radio Corporation.............. 28, 29 G & G Radio Supply Co. ................. 155 Gardner Electronics Co. ............0++0. 147 Garfield Company, Oliver................. 145 EIT EES SE ee 28 General Motors Corp. ...... Wedprews ss cess 10 Goodheart, R. E. ............ Sappanescses 136 Greenice Tool Co. ......cccccccccescceeess 94 Harje Gales Co. ......ccccee. buptasvecenh 104 Hartley Products Co. ............ beosabas 146 Sniwee RAINS Cais ING. os ovceccccccccvecs 154 SEY Oiicg Fa Ud pcvivmcnecesdcwecceces 136 Heald Engineering College...............-. 104 Heath Company ...........++-+.+++ 80, BI,
82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93 SN TIRGeD DORGOS. oc ccc scccvcesesosess 132 Hershel Radio Corp. ...........00-+-0005 160 Hi-Lo TV Antenna Corp. ...........-+-++ 97 Hughes Research and Development Labora-
QUOT a i cicsvoncses pewsbhoostedsdc coves 77 indiana Technical College..............-- 145 International Business Machines Corp. ..26, 27 4. J. Glass Electronics Co. ............-+- 126 Jazztone Society, The......... Cbs eodecces 152 Jerrold Electronics Corp. .........+++0++ 23
ADVERTISER PAGE
Kopelove Electronics Co. ......0++.++0+++-153
L M B Box Chassis........ Sbecesesesores 132 Lafayette Radio .............. ovbnes 128, 129 Lampkin Laboratories, Inc. ............-- 120 Lektron Specialties ............ divendahas 162 McGee Radio Company........ vodepes tiny tan McGraw-Hill Book Co. ..........+e0eeeees 98 Se, TR, GO, TOs caw ssatcabavescece> 160 Mallory & Co., Inc., P. R....... Fourth Cover Merit Coil & Transformer Corp. .......... 151 Milwaukee School of Engineering......... itt Moss Electronic Distributing Co. ....116, 117 COIS 3c cctcrvcascctaredwecesenscbose 141 National Radio Institute..... evevecs 3, 19, 20 National Gehowls 2... ccccccccccccssas 7, 153 Newark Electric Company................ 166 North American Phillips Co., Inc. ........ 30 Oelrich Publications ......... eeNssecepece 162 Olson Radio Warehouse..... everecceceoes 157 Pampa Electronics Corp. ........ peeh eee es 138 Peak Electronics Company...............- 166 Phaostron Instrument & Electronic Co. ... 24 Philco Techrep Division.............+++.- 165 Precise Development Corp. ............+-- 12 Precision Electronics ...........++0se00++ 143 Progressive “Edu-Kits,” Inc. ........---.- 124 R. C. A. Institutes, Inc. ..........66-- 79, 98 MW Electroates ... wc ccccscccccccccccees 126 Radiart Corporation, The...........+.+.-. 6 Radio Corporation of America......... 34, 121 Radio Ham Shack, Inc. ...........-000055 172 Radio Shack of Boston...........-+-+.+5- 113 Radio-Television Training Association..... 25 Rad Tel Tae SO. oo. cccvccccccccccccscs 102 Ram Electronics Sales Co. .........++-+++ 114 Raytheon Manufacturing Company
pple Cunekddohda cake e650 tow Second Cover Remington Rand, Inc. ............-06e0e 16 Rex Radio Supply Company.............-- 114 Rinehart & Co., Inc. .......+.++-. 95, 103, 142 Sams & Co., Inc., Howard W. ........ 16, 167 Geott-Mitehell ...ccccsvccsecccvesccccess 152 Service instrument Co, .........---0+00+- 100 Shure Brothers, tmc. ......-...+++eeeee0: 149 Sprayberry Academy of Radio............ 31 Stan-Burn Radio & Electronics Co. .......156 Stanley Electronics Corp. ..........+.+0++ 159 Stevens Walden, Inc. .........- ivaees ee CFR vi wisccasdocns sabes ictadevepive 170 Tech-Master Products Co. Swbiee was wieoe San Texas Crystals .........ccecececccees a VRRPORD iindwsce icons cveudsecese juNeall 148 Tran-Kit Electronics Co. ..........--++++5 168 Transvision, INC. ..........ceeeerercecees 152 Triplett Electrical Instrument Corp. Third Cover Tri-State College ........ccseseceeccecess 147 Tube Mart ..........- évapicdespoueeeaed 104 Tung-Sol Electric Co. ........-.-+ ebviesee 22 United Audio Center.............eeee00++ 98 United Catalogue Publishers, ine. $oouedes 164 University Loudspeakers ...........++++++ 142 V.S.1. Television School........ bsepveunee 162 Valparaiso Technical Institute............ 169 Video Electric Co. ......... ecvcccccel Sa, 168 Western Radio ............. hayes éesbons seen Western Television Institute. . peeusseeeseceee World Radio Laboratories..... piaevescnas ter
Zytron Tube Company..........-++-+++++-426 ff
RADIO & TELEVISION NEWS
PREC vicini BUIL! old T Electr WALI Fabco ham,
Nebra: DISGL Discou Write
VISIO}
AN/AI “Tg.,* lus ;
escril ciates, WANT eeivers Collins Inverte conditi tries, I phone ART—' 13/T47 eters, $325 .0¢
BEFOR Surplus tronics. BC-221 mitters, Electro
Florida
Janua
Y, y,
¢
RATE: 50¢ = ye. , 10 words. March Issue closes Janu Send order and remittance to: name a TELEVisiON “NEWS. 366 Madison Ave., N. i
RADIO ENGINEERING
COMPLETE radio, electronics theory & practice; television ; broadcasting; servicing; aviation, ma- rine, police radio. 18 or 21 months. Catalog. Val- paraiso Technical Institute, Dept. N, Valparaiso,
FOR SALE
PRECISION 1054 tester 20,000 r/v $90. N. Y. vicinity. SC 4-9857.
BUILD your own television test instrument from old TV set. Complete instructions $2.00. Sterling Electronic Co., 129 W. Long Ave., New Castle, Pa.
WALKIE-talkie for less than $10.00. Plans 50¢. Fabco Electronics, 7400-R Jackson Pk., Birming- ham, Michigan.
ONE of the original General Electric FM receiv- ers covering the old band 44-48 mc. $10.00. Box 51 % RADIO & TV NEWS
DIAGRAMS for repairing radios $1.00. Television $2.00. Give make, model. Diagram Service, Box 672-RN, Hartford 1, Conn.
TUBES—TV, Radio, Transmitting And Industrial Types At Sensibly Low Prices. New, Guaranteed, Ist Quality, Top Name Brands Only. Write For Free Catalog or Call Walker 5-7000, Barry Elec- tronics Corp., 512 Broadway, New York 12N, N. Y.
DIAGRAMS—Radios, Amplifiers, Changers, $1.00 Each. Television Service Data $2.00. Unknown Models, Give Tube Layout And Part Numbers. Kramer’s Radio Service. Dept. 656, 36 Columbus Ave., New York 23, N. Y.
COMPLETE Television Sets $11.95. 1115 Rambler, Pottstown, Pa. TUBES—RK715A, 725A, 706AY, G1299, 803, $1.75 each. Allied Electronics, 111 North 41, Omaha, Nebraska.
Jones TV,
CASH Paid! Sell your surplus electronic tubes. Want unused, clean transmitting, special purpose, receiving, TV types, magnetrons, Klystrons, broad- cast, ete. Also want military & commercial lab test and communications gear. We swap too, for tubes or choice equipment. Send specific details in first letter. For a fair deal write, wire or tele- phone: Barry, 512 Broadway, New York 12, N. Y. WaAlker 5-7000.
BEFORE You Sell Tell Rex! Wanted—Surplus Military And Commercial Aircraft Electronics: BC-788, 1-152, ARN-7, ARC-1, ARC-3, BC-221, RTA-1B, ART-13, DY-21, APN-9, transmitters, re- ceivers, test equipment, etc.! Wanted-—Electronic Tubes: Broadcast, transmitting, receiving, Magne- trons, Klystrons, miniature, sub-miniature, rug- gedized, etc.! Top Prices Paid! For Fattest Checks, Sell to Rex! Write or phone description for imme- diate action. Bob Sanett, W6REX, 1524 8. Edris Drive, Los Angeles 35, Calif. Phones: REpublic 5-0215, CRestview 1-3856.
REPAIRS AND SERVICING
HIGH Fidelity Speakers Repaired. Amprite Speaker Service, 70 Vesey St., N. Y. 7, N. ¥. Ba. 7-2580.
TAPE RECORDERS
RECORDERS, Tape, Hi-Fi. Wholesale Prices. Catalogue. Klarston, 215 E. 88th St., N. Y. C. 28.
PRE-RECORDED Tapes, Recorders, Accessories. Unusual Values, Catalog. Efsco Sales, 270-E Con- cord Avenue, West Hempstead, N. Y.
TAPE Recorders, Tape. Unusual Values. Free ees. Dressner 69-02 R, 174 St., Flushing 65,
INSTRUCTION
ENGINEERING Degrees earned by home study. (Residential courses also available). Pacific Inter- national University, (formerly American College of Engineering), Box 27724-C, Hollywood 27, Califor- nia.
KNOW Morse Code in minutes. Revolutionary Code Teacher proved 10 years. 50¢ and self- addressed stamped-envelope to “Philkoda-T”, 7120 Lahser, Birmingham, Mich.
DISGUSTED with ‘‘HI’’ HI-FI Prices? Unusual Discounts on all your High Fidelity requirements. Write now. Key Electronics Co., 120 Liberty St., N. Y¥. 6, N. Y.
WANTED
CYLINDER and old disc phonographs. Edison Conqueror, Idelia, and Oratorio models. Berliner Gramophones and Zono-o-phones, Columbia cylin- der Graphophones, and coin-operated cylinder phonos. Want old catalogues and literature on early phonos prior to 1919. Will pay cash or trade late hi-fi components. Box 50 % RADIO & TELE- VISION NEWS. AN/APR-4, AN/APR-9, other ‘““APR-,”’ ““ARR-,”” “TS-,’’ ARC-1, ARC-3, ART-13, everything sur- lus; Tubes, Manuals, Laboratory equipment. escribe, price in first letter. Engineering Asso- ciates, 434 Patterson Rd., Dayton 9, Ohio.
WANTED: Receiver R5/ARN-7, MN-62A Trans- eeivers, RT18/ARC-1, AN/ARC-3, BC-788C, I-152C, Collins, Bendix equipment, Test Sets, Dynamotors, Inverters. We pay highest prices. Advise quantity, condition, price first letter. Aircraft Radio Indus- tries, Inc., 15 East 40th St., New York City, tele- phone LE xington 2-6254.
ART—13/T47A Transmitters, $175.00; ART— 13/T47 Transmitters, $125.00; BC-788 C Altim- eters, $175.00; ARC-3 Transceiver Complete, $325.00; R5/ARN-7 Radio Compass, $175.00; BC- 348 Rec’r Modified, $25.00; BC-348 Rec’r Unmod- ified, $50.00; ARC-1 Transceiver, $300.00 ; BC-342 Ree’r, $50.00; BC-312 Rec’r, $40.00; I-152-C In- dicator, $50.00. Ship Via Express, C.0.D. Sub- ject To Inspection To H. Finnegan, 49 Washington Ave., Little Ferry,
BC221’s WANTED—Highest cash ‘price ‘for “‘BC- 221’s paid even more if the unit has modutation and hasn't been tampered with. Original Book needed. Write giving Model No. to Bolton Laboratories, Inc., Bolton, Mass.
BEFORE You Sell—Check With Rex! Wanted: Surplus military and commercial aircraft elec- tronics. BC-788, 1-152, ARN-7, ARC-1, ARC-3, BC-221, RTAIB, ART-13, DY-21, APN-9, trans- mitters, receivers, test equipment, ete. Also Want Electronic Tubes: broadcast, transmitting, receiv- ing, Magnetrons, Klystrons, miniatures, sub-minia- tures, ruggedized, etc. For Top Prices Contact: Bob Sanett, W6Rex, 1524 8. Edris Dr., Los An- geles 35, Cal. Phone: REpublic 5-0215.
WANTED: ART-13 transmitters and parts—also
ARC-1, ARC-3, and ARN-7. Have requirement for
ARN-6 material, Iron Core Loops, need all types
Collins and Bendix Aircraft Radio equipment.
Florida Aircraft Radio & Marine, Inc. » P.O. Box
ye a Airport Branch, Miami 48, orida
January, 1957
CORRESPONDENCE COURSES
USED Correspondence Courses and Books sold and rented. Money back guarantee. Catalog free. (Courses bought.) Lee Mountain, Pisgah, Ala.
RECORDS
LONG Playing Records 20 to 50% Discount Brand New Factory Fresh Unplayed—All Labels—Send 20c for catalogue to South West. Record, 1108 Winbern, Houston 4, Texas.
MISCELLANEOUS
EAVESDROP with a pack of cigarettes, miniature transistorized radio transmitter. Complete Dia- grams and Instructions. $1.25, C. Carrier Co., 734 15th St., N.W., Washington, D. C.
TELEPHONE Extension in your car. Answer your home telephone by radio from your car. Complete diagrams and instructions. $1.25, C. Carrier Co., 734 15th St., N.W., Washington, D. Cc.
(ka for the 5 TOP QUALITY brands of
‘TUBES
AT SENSIBLE PRICES!
© 90-Day RETMA guarantee @ Brand New © Individually boxed First quality only T
WRITE FOR beat) Pavine AND RICE LIST, FR
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35 50 . ee -20 Over 4000 ‘types in
*(SURPLUS)
mise? Oe ‘ ang many, many others. stock!
2 COLOR TUBE CARTONS
Keeps your tube stock neat. New safety partition prevents tube breakage. yt ag ng litho-
raphed in gios red and black. The. most distinctive tube carton
Write for
too. of any one size.
stacker holds
Ministacker ... GT
5” DUMONT SCOPE MODEL 274A AT LESS THAN HALF PRICE!
Genuine Dumont model 274A, S$” oscilloscopes, regularly sold for $150, now available for LESS THAN HALF PRICE! Look at these features; Fre- quency response within 50% from Fay A 200,000 cps with recurrent sweeps from 8 to 30,000 cps. Similar X and y sag ee and AO for in-
$65.00
wet. only guaranteed. SPECIAL! F.O.B. N.Y.C.....
eereeee
on Famous
NATIONAL HIGH FIDELITY
AM/FM Tuner Net $189.95 20 Watt Ampi Net 84.95
a) H5 Preamp! Net 49.95
Tr Net $324.85 COMPLETE only $18995
with l0W, instead of 20W. Amp.—Net $269.90 COMPLETE only ${4Q95
Limited Quantity at our ay oy! or Mail orders 25%, Deposit—Balance C Full Line of Hi Fi components, Tape Teoasdiea. etc.
Get our Special Prices
CENTER ELECTRONICS CoO.
Dept. N 72 Cortlandt St. New York 7, N. Y.
TEST EQUIPMENT BARGAINS! ABSORPTION WAVEMETER. GEN'L. Radio type 758A 55-400 MCS. (Worth $40.00) NEW! 12.50 5” OSCILLOSCOPE. Dumont 274A. Vy. goo 5” OSCILLOSCOP
SOPE. RCA go 5.00 CHANNEL MARKER. ney “mega-marker® q 49.50
. L.N $2: —— Measurements Corp. model 71. Excellent con . sses.0 a pe (G60) METER. “Measurements Corp. R. ck mtd. with probe and ali enite, -$125.00 “gpur™ (Events PER UNIT TIME) METER. Berkele model 554. ~ digit, tpg speed onunner, Hang. $1000) L. Ne : age 7 SIGNAL GENERATOR: 6A 000 Mcs. N 1 SIGNAL, GENERATOR. Measurements Corp. mode! 80. 0-400 Mcs. Vy. good $350.00 S19n ah GENERATOR. mts Corp model FM. 86-110 Mcs. 30 Ke. deviation. "Excellent pane $175.00
TRANSFORMER SPECIAL!
3100-0-3100 volts @ Ya a mpl tet mags tapped for 98-104-1 0-116-12 volts, 60 cycles . SECONDARY: 3100 volts each side of center 1S KV impregnated mica re. } rated. Meas. 9” L x 8” H x 742” W. New, guaranteed. Shpg. wgt. 60 Ibs
WRITE FOR “BARRY'S GREEN SHEET." FREE!
TERMS: 25% deposit with order. patance | & o. D. All merchandise guaranteed, F.0.8.
B ARRY ELECTRONICS
512 Broadway, Dept. RN, N.Y. 12, N.Y. Call Day or Night—24 Hour Phone Service Phone: WAlker re soe
171
@ 500 Conserva-
RADIO & TELEVISION NEWS
TUBE
SPECIALISTS to the WORLD
SELECT THE TUBES YOU NEED FROM ONE OF THE MOST COMPLETE TUBE INVENTORIES IN THE WORLD
First Quality — Fully Guaranteed — No Seconds
RECEIVING Aes oe
TRANSMITTING Tl
OA3/VR7S .86 0B3/VR9O0 .73 0C3/VR105 .68 0D3/VR150 .68 1B22 1.25
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RAUROSAAARAARARORRaAe
MRO HH Wu AON PNOKD hee
We urgently need for government con- tracts military electronic equipment, such as: BC3}2, BC342, BC348, ART13, APR4, ARCI, ARC3, ARN6, ARN7, BC221, BC788, BC610, and many others. State conditions, type and best price.
New
ARAORTAASORDR
oo
2” SIZE METER SPECIALS
~ _ PEPSMNENONHraNOMN SNS ae
*OOanINN
MILLIAMMETER - MILLIAMMETER. 300 mill SCALE
Pe Rn 4 with order or Aire Soper Sates c.0.D. © days net to rated accts. ices F.O.B8. our warehouse,
Special Quantity noabonharey All Inquiries Answered
WE SHIP TO ALL THE WORLD. CORRESPONDENCE IN ALL LANGUAGES. CABLE ADDRESS: HAMSHACK NEW YORK Pers :
370 Greenwich Street, New York 13, N.Y. Telephone CAnal 6-8446
PRINTED IN U.S.A. RADIO & TELEVISION NEWS
this u
tests AC 20,000 ¢ Milliam Ohms ( Decibel easy-to- longest
BuRTON BROWNE ADVERTISING
advan
— Molde and shur without | shorts. L replace re positions
TRIPLE Bluffton
vanuary, '73/
171
you can’t match ‘YRipeay? model 630 VOM
ate «~ SPEED — ACCURACY DURABILITY
CONVENIENCE!
sure grip battery contacts Mmm st
Balanced double-spring tension grip assures permanent contact! .
heavy molded case
—\" thick for high impact. Fully insulated.
“this wide-range model tests AC-DC Volts (DC at
20,000 O/V); DC Microamperes, Milliamperes, and Amperes; Ohms (to 100 Megohms); Decibel and Output. Its easy-to-read scales are the
longest in this type tester.”
Les7 ‘gn
No protruding knobs on switch or ohms control—both are flush with the panel.
—Only one switch; (fully enclosed) selects both circuit and range. Just turn the switch and make your reading.
BuRTON BROWNE ADVERTISING
for most efficient meter use
— Banana jacks and plugs on — — With every Model 630 you test leads are best. Alligator clips receive complete, simplified are provided to slip on test prods instructions on how to use and for extra convenience. maintain most efficiently. _for convenience no slip feature > a
advanced engineering
ing Four rubber feet furnished
; zal as standard equipment fit —Molded mounting for resistors —Available as an extra (only in back of tie ea aes and shunts allow direct connections 50c), this special stand tilts Saige tt Gtetinds oe without cabling. No chance for meter at best angle for P smoorh eatnces
shorts. Longer life and easy-to- easy reading replace resistors in their marked
one MODEL 630|$395°
TRIPLETT ELECTRICAL INSTRUMENT CO. Bluffton, Ohio
Ever notice how some capacitors fail before their time? In just a few weeks, especially in a high ripple circuit, they begin to develop hum.
This is due to loss of capacitance, and it’s a common ailment of capacitors with plain foil cathodes.
You’ll never have this trouble with Mallory FP’s and popular Mallory tubular electrolytics . . . because they have etched cathode construction. It’s a standard feature of Mallory electrolytics that insures against ‘“‘missing microfarads.”’
See your local Mallory distributor for full facts on why etched cathode is important to you— and to your customers!
P. R. MALLORY & CO. 1 INDIANAPOLIS 6, INDIANA